Add doc8 documentation style checking

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

1 files changed, 2 insertions, 1 deletions

diff --git a/setup.py b/setup.py
index 3319c82d..e349167d 100755
--- a/setup.py
+++ b/setup.py
@@ -43,7 +43,8 @@ EXTRAS_REQUIRE = {
     # development only dependencies:  install with 'pip install -e .[dev]'
     'dev': ["mock ; python_version<'3.6'",  # for python 3.5 we need the third party mock module
             'pytest', 'codecov', 'pytest-cov', 'pytest-mock', 'tox', 'pylint',
-            'sphinx', 'sphinx-rtd-theme', 'sphinx-autobuild', 'invoke', 'twine>=1.11',
+            'sphinx', 'sphinx-rtd-theme', 'sphinx-autobuild', 'doc8',
+            'invoke', 'twine>=1.11',
             ]
 }