Add doc8 documentation style checking

- add dev dependency
- add doc8 to tasks.py
- fix all doc8 errors

4 files changed, 40 insertions, 38 deletions

diff --git a/docs/overview/alternatives.rst b/docs/overview/alternatives.rst
index e8e8e3b3..63977334 100644
--- a/docs/overview/alternatives.rst
+++ b/docs/overview/alternatives.rst
@@ -2,10 +2,11 @@ Alternatives
 ============
 
 For programs that do not interact with the user in a continuous loop - programs
-that simply accept a set of arguments from the command line, return results, and
-do not keep the user within the program's environment - all you need are sys_\
-.argv (the command-line arguments) and argparse_ (for parsing UNIX-style options
-and flags).  Though some people may prefer docopt_ or click_ to argparse_.
+that simply accept a set of arguments from the command line, return results,
+and do not keep the user within the program's environment - all you need are
+sys_\ .argv (the command-line arguments) and argparse_ (for parsing UNIX-style
+options and flags).  Though some people may prefer docopt_ or click_ to
+argparse_.
 
 .. _sys: https://docs.python.org/3/library/sys.html
 .. _argparse: https://docs.python.org/3/library/argparse.html
@@ -16,15 +17,16 @@ and flags).  Though some people may prefer docopt_ or click_ to argparse_.
 The curses_ module produces applications that interact via a plaintext terminal
 window, but are not limited to simple text input and output; they can paint the
 screen with options that are selected from using the cursor keys.  However,
-programming a curses_-based application is not as straightforward as using cmd_.
+programming a curses_-based application is not as straightforward as using
+cmd_.
 
 .. _curses: https://docs.python.org/3/library/curses.html
 .. _cmd: https://docs.python.org/3/library/cmd.html
 
-Several Python packages exist for building interactive command-line applications
-approximately similar in concept to cmd_ applications.  None of them share
-``cmd2``'s close ties to cmd_, but they may be worth investigating nonetheless.
-Two of the most mature and full featured are:
+Several Python packages exist for building interactive command-line
+applications approximately similar in concept to cmd_ applications.  None of
+them share ``cmd2``'s close ties to cmd_, but they may be worth investigating
+nonetheless. Two of the most mature and full featured are:
 
   * `Python Prompt Toolkit`_
   * Click_
@@ -32,24 +34,21 @@ Two of the most mature and full featured are:
 .. _`Python Prompt Toolkit`: https://github.com/jonathanslenders/python-prompt-toolkit
 
 `Python Prompt Toolkit`_ is a library for building powerful interactive command
-lines and terminal applications in Python.  It provides a lot of advanced visual
-features like syntax highlighting, bottom bars, and the ability to create
-fullscreen apps.
+lines and terminal applications in Python.  It provides a lot of advanced
+visual features like syntax highlighting, bottom bars, and the ability to
+create fullscreen apps.
 
 Click_ is a Python package for creating beautiful command line interfaces in a
 composable way with as little code as necessary.  It is more geared towards
 command line utilities instead of command line interpreters, but it can be used
 for either.
 
-Getting a working command-interpreter application based on either `Python Prompt
-Toolkit`_ or Click_ requires a good deal more effort and boilerplate code than
-``cmd2``.  ``cmd2`` focuses on providing an excellent out-of-the-box experience
-with as many useful features as possible built in for free with as little work
-required on the developer's part as possible.  We believe that ``cmd2`` provides
-developers the easiest way to write a command-line interpreter, while allowing a
-good experience for end users.  If you are seeking a visually richer end-user
-experience and don't mind investing more development time, we would recommend
-checking out `Python Prompt Toolkit`_.
-
-In the future, we may investigate options for incorporating the usage of `Python
-Prompt Toolkit`_ and/or Click_ into ``cmd2`` applications.
+Getting a working command-interpreter application based on either `Python
+Prompt Toolkit`_ or Click_ requires a good deal more effort and boilerplate
+code than ``cmd2``.  ``cmd2`` focuses on providing an excellent out-of-the-box
+experience with as many useful features as possible built in for free with as
+little work required on the developer's part as possible.  We believe that
+``cmd2`` provides developers the easiest way to write a command-line
+interpreter, while allowing a good experience for end users.  If you are
+seeking a visually richer end-user experience and don't mind investing more
+development time, we would recommend checking out `Python Prompt Toolkit`_.
diff --git a/docs/overview/installation.rst b/docs/overview/installation.rst
index fc44e740..9f1209b6 100644
--- a/docs/overview/installation.rst
+++ b/docs/overview/installation.rst
@@ -104,7 +104,8 @@ Upgrade an already installed ``cmd2`` to the latest version from PyPI_::
 
     pip install -U cmd2
 
-This will upgrade to the newest stable version of ``cmd2`` and will also upgrade any dependencies if necessary.
+This will upgrade to the newest stable version of ``cmd2`` and will also
+upgrade any dependencies if necessary.
 
 
 Uninstalling cmd2
@@ -121,8 +122,8 @@ macOS comes with the `libedit <http://thrysoee.dk/editline/>`_ library which is
 similar, but not identical, to GNU Readline. Tab-completion for ``cmd2``
 applications is only tested against GNU Readline.
 
-There are several ways GNU Readline can be installed within a Python environment
-on a Mac, detailed in the following subsections.
+There are several ways GNU Readline can be installed within a Python
+environment on a Mac, detailed in the following subsections.
 
 
 gnureadline Python module
diff --git a/docs/overview/integrating.rst b/docs/overview/integrating.rst
index 146e5e35..e28df1a7 100644
--- a/docs/overview/integrating.rst
+++ b/docs/overview/integrating.rst
@@ -9,13 +9,13 @@ include ``cmd2``. Make sure your ``setup.py`` includes the following::
   ]
 
 The ``cmd2`` project uses `Semantic Versioning <https://semver.org>`_, which
-means that any incompatible API changes will be release with a new major version
-number. We recommend that you follow the advice given by the Python Packaging
-User Guide related to `install_requires
+means that any incompatible API changes will be release with a new major
+version number. We recommend that you follow the advice given by the Python
+Packaging User Guide related to `install_requires
 <https://packaging.python.org/discussions/install-requires-vs-requirements/>`_.
 By setting an upper bound on the allowed version, you can ensure that your
-project does not inadvertently get installed with an incompatible future version
-of ``cmd2``.
+project does not inadvertently get installed with an incompatible future
+version of ``cmd2``.
 
 
 Windows Considerations
@@ -23,7 +23,8 @@ Windows Considerations
 
 If you would like to use :ref:`features/completion:Completion`, and you want
 your application to run on Windows, you will need to ensure you install the
-``pyreadline`` package. Make sure to include the following in your ``setup.py``::
+``pyreadline`` package. Make sure to include the following in your
+``setup.py``::
 
   install_requires=[
     'cmd2>=1,<2',
diff --git a/docs/overview/summary.rst b/docs/overview/summary.rst
index b59c86c2..9285014c 100644
--- a/docs/overview/summary.rst
+++ b/docs/overview/summary.rst
@@ -5,17 +5,18 @@ Building a new `REPL <https://en.wikipedia.org/wiki/Read–eval–print_loop>`_
 `Command Line Interface <https://en.wikipedia.org/wiki/Command-line_interface>`_
 application?
 
-Already built an application that uses cmd_ from the python standard library and
-want to add more functionality with very little work?
+Already built an application that uses cmd_ from the python standard library
+and want to add more functionality with very little work?
 
 ``cmd2`` is a powerful python library for building command line applications.
 Start here to find out if this library is a good fit for your needs.
 
 * :ref:`overview/installation:Installation Instructions` - how to install
   ``cmd2`` and associated optional dependencies
-* :ref:`examples/first_app:First Application` - a sample application showing 8 key features of ``cmd2``
-* :ref:`overview/integrating:Integrate cmd2 Into Your Project` - adding ``cmd2``
-  to your project
+* :ref:`examples/first_app:First Application` - a sample application showing 8
+  key features of ``cmd2``
+* :ref:`overview/integrating:Integrate cmd2 Into Your Project` - adding
+  ``cmd2`` to your project
 * :ref:`overview/alternatives:Alternatives` - other python packages that might
   meet your needs
 * :ref:`overview/resources:Resources` - related links and other materials