Added info on semantic versioning and branching strategy to CONTRIBUTING.md

Also:
- Added isort to Pipenv dev
- Added setup.cfg to make it easy to run flake8, doc8, and isort directly from the command line without using invoke
- Ran isort to sort includes

13 files changed, 48 insertions, 21 deletions

diff --git a/tests/conftest.py b/tests/conftest.py
index 9ee8da19..60074f5c 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -3,7 +3,7 @@
 Cmd2 unit/functional testing
 """
 import sys
-from contextlib import redirect_stdout, redirect_stderr
+from contextlib import redirect_stderr, redirect_stdout
 from typing import List, Optional, Union
 from unittest import mock
 
@@ -12,7 +12,6 @@ from pytest import fixture
 import cmd2
 from cmd2.utils import StdSim
 
-
 # Prefer statically linked gnureadline if available (for macOS compatibility due to issues with libedit)
 try:
     import gnureadline as readline
diff --git a/tests/pyscript/environment.py b/tests/pyscript/environment.py
index 5e4d93d6..f1182c82 100644
--- a/tests/pyscript/environment.py
+++ b/tests/pyscript/environment.py
@@ -2,6 +2,7 @@
 # Tests that cmd2 populates __name__, __file__, and sets sys.path[0] to our directory
 import os
 import sys
+
 app.cmd_echo = True
 
 if __name__ != '__main__':
diff --git a/tests/test_argparse.py b/tests/test_argparse.py
index db6dea21..daf43497 100644
--- a/tests/test_argparse.py
+++ b/tests/test_argparse.py
@@ -9,6 +9,7 @@ from typing import Optional
 import pytest
 
 import cmd2
+
 from .conftest import run_cmd
 
 # Prefer statically linked gnureadline if available (for macOS compatibility due to issues with libedit)
diff --git a/tests/test_argparse_completer.py b/tests/test_argparse_completer.py
index 9e635a42..4313647b 100644
--- a/tests/test_argparse_completer.py
+++ b/tests/test_argparse_completer.py
@@ -9,9 +9,10 @@ from typing import List
 import pytest
 
 import cmd2
-from cmd2 import with_argparser, Cmd2ArgumentParser, CompletionItem
+from cmd2 import Cmd2ArgumentParser, CompletionItem, with_argparser
 from cmd2.utils import CompletionError, StdSim, basic_complete
-from .conftest import run_cmd, complete_tester
+
+from .conftest import complete_tester, run_cmd
 
 # Lists used in our tests (there is a mix of sorted and unsorted on purpose)
 static_int_choices_list = [-1, 1, -2, 2, 0, -12]
diff --git a/tests/test_argparse_custom.py b/tests/test_argparse_custom.py
index 92b2ecb4..f4db12b6 100644
--- a/tests/test_argparse_custom.py
+++ b/tests/test_argparse_custom.py
@@ -9,6 +9,7 @@ import pytest
 import cmd2
 from cmd2 import Cmd2ArgumentParser, constants
 from cmd2.argparse_custom import generate_range_error
+
 from .conftest import run_cmd
 
 
diff --git a/tests/test_cmd2.py b/tests/test_cmd2.py
index fdeea9aa..33f75c9e 100755
--- a/tests/test_cmd2.py
+++ b/tests/test_cmd2.py
@@ -13,16 +13,27 @@ from code import InteractiveConsole
 
 import pytest
 
+import cmd2
+from cmd2 import COMMAND_NAME, ansi, clipboard, constants, exceptions, plugin, utils
+
+from .conftest import (
+    HELP_HISTORY,
+    SHORTCUTS_TXT,
+    SHOW_LONG,
+    SHOW_TXT,
+    complete_tester,
+    normalize,
+    odd_file_names,
+    run_cmd,
+    verify_help_text,
+)
+
 # Python 3.5 had some regressions in the unitest.mock module, so use 3rd party mock if available
 try:
     import mock
 except ImportError:
     from unittest import mock
 
-import cmd2
-from cmd2 import ansi, clipboard, constants, exceptions, plugin, utils, COMMAND_NAME
-from .conftest import (run_cmd, normalize, verify_help_text, HELP_HISTORY, SHORTCUTS_TXT, SHOW_TXT,
-                       SHOW_LONG, complete_tester, odd_file_names)
 
 def CreateOutsimApp():
     c = cmd2.Cmd()
diff --git a/tests/test_completion.py b/tests/test_completion.py
index e13d87de..a380d43a 100755
--- a/tests/test_completion.py
+++ b/tests/test_completion.py
@@ -22,6 +22,7 @@ import pytest
 import cmd2
 from cmd2 import utils
 from examples.subcommands import SubcommandsExample
+
 from .conftest import complete_tester, normalize, run_cmd
 
 # List of strings used with completion functions
diff --git a/tests/test_history.py b/tests/test_history.py
index 11f189f6..6fa16ad8 100755
--- a/tests/test_history.py
+++ b/tests/test_history.py
@@ -3,22 +3,23 @@
 """
 Test history functions of cmd2
 """
-import tempfile
 import os
+import tempfile
 
 import pytest
 
+import cmd2
 # Python 3.5 had some regressions in the unitest.mock module, so use
 # 3rd party mock if available
 from cmd2.parsing import StatementParser
 
+from .conftest import HELP_HISTORY, normalize, run_cmd
+
 try:
     import mock
 except ImportError:
     from unittest import mock
 
-import cmd2
-from .conftest import run_cmd, normalize, HELP_HISTORY
 
 
 #
diff --git a/tests/test_parsing.py b/tests/test_parsing.py
index 5f363320..c2c242fe 100755
--- a/tests/test_parsing.py
+++ b/tests/test_parsing.py
@@ -10,6 +10,7 @@ import cmd2
 from cmd2 import constants, exceptions, utils
 from cmd2.parsing import StatementParser, shlex_split
 
+
 @pytest.fixture
 def parser():
     parser = StatementParser(
diff --git a/tests/test_plugin.py b/tests/test_plugin.py
index bb7753f0..132361a6 100644
--- a/tests/test_plugin.py
+++ b/tests/test_plugin.py
@@ -8,14 +8,15 @@ import sys
 
 import pytest
 
+import cmd2
+from cmd2 import Cmd2ArgumentParser, exceptions, plugin, with_argparser
+
 # Python 3.5 had some regressions in the unitest.mock module, so use 3rd party mock if available
 try:
     import mock
 except ImportError:
     from unittest import mock
 
-import cmd2
-from cmd2 import exceptions, plugin, Cmd2ArgumentParser, with_argparser
 
 
 class Plugin:
diff --git a/tests/test_run_pyscript.py b/tests/test_run_pyscript.py
index 6110e3ac..8cfd8578 100644
--- a/tests/test_run_pyscript.py
+++ b/tests/test_run_pyscript.py
@@ -9,7 +9,8 @@ import os
 import pytest
 
 from cmd2 import plugin, utils
-from .conftest import run_cmd, odd_file_names
+
+from .conftest import odd_file_names, run_cmd
 
 # Python 3.5 had some regressions in the unitest.mock module, so use 3rd party mock if available
 try:
diff --git a/tests/test_table_creator.py b/tests/test_table_creator.py
index 917ba5cc..ed53efa6 100644
--- a/tests/test_table_creator.py
+++ b/tests/test_table_creator.py
@@ -6,8 +6,15 @@ Unit testing for cmd2/table_creator.py module
 import pytest
 
 from cmd2 import ansi
-from cmd2.table_creator import (AlternatingTable, BorderedTable, Column, HorizontalAlignment,
-                                SimpleTable, TableCreator, VerticalAlignment)
+from cmd2.table_creator import (
+    AlternatingTable,
+    BorderedTable,
+    Column,
+    HorizontalAlignment,
+    SimpleTable,
+    TableCreator,
+    VerticalAlignment,
+)
 
 
 def test_column_creation():
diff --git a/tests/test_transcript.py b/tests/test_transcript.py
index aa6f8c4e..69389b7f 100644
--- a/tests/test_transcript.py
+++ b/tests/test_transcript.py
@@ -5,18 +5,19 @@ Cmd2 functional testing based on transcript
 """
 import argparse
 import os
-import sys
-import re
 import random
+import re
+import sys
 import tempfile
-
 from unittest import mock
+
 import pytest
 
 import cmd2
-from .conftest import run_cmd, verify_help_text
 from cmd2 import transcript
-from cmd2.utils import StdSim, Settable
+from cmd2.utils import Settable, StdSim
+
+from .conftest import run_cmd, verify_help_text
 
 
 class CmdLineApp(cmd2.Cmd):