Modified setup.py and README.md to make pyreadline a dependency on Windwos

Also:
- bumped version to 0.7.9a
- updated changelog

Author: tleonhardt

CHANGELOG.md

@@ -1,3 +1,11 @@
+## 0.7.9 (TBD)
+
+* Bug Fixes
+    * Fixed a couple broken examples
+* Enhancements
+    * Improved documentation for modifying shortcuts (command aliases)
+    * Made ``pyreadline`` a dependency on Windows to ensure tab-completion works
+    
 ## 0.7.8 (November 8, 2017)
 
 * Bug Fixes

README.md

@@ -48,7 +48,8 @@ pip install -U cmd2
 
 cmd2 works with Python 2.7 and Python 3.3+ on Windows, macOS, and Linux. It is pure Python code with
 the only 3rd-party dependencies being on [six](https://pypi.python.org/pypi/six),
-[pyparsing](http://pyparsing.wikispaces.com), and [pyperclip](https://github.com/asweigart/pyperclip).
+[pyparsing](http://pyparsing.wikispaces.com), and [pyperclip](https://github.com/asweigart/pyperclip) 
+(on Windows, [pyreadline](https://pypi.python.org/pypi/pyreadline) is an additional dependency).
 
 For information on other installation options, see
 [Installation Instructions](https://cmd2.readthedocs.io/en/latest/install.html) in the cmd2

cmd2.py

@@ -105,7 +105,7 @@
 else:
     BROKEN_PIPE_ERROR = IOError
 
-__version__ = '0.7.8'
+__version__ = '0.7.9a'
 
 # Pyparsing enablePackrat() can greatly speed up parsing, but problems have been seen in Python 3 in the past
 pyparsing.ParserElement.enablePackrat()

setup.py

@@ -3,9 +3,10 @@
 """
 Setuptools setup file, used to install or test 'cmd2'
 """
+import sys
 from setuptools import setup
 
-VERSION = '0.7.8'
+VERSION = '0.7.9a'
 DESCRIPTION = "cmd2 - a tool for building interactive command line applications in Python"
 LONG_DESCRIPTION = """cmd2 is a tool for building interactive command line applications in Python. Its goal is to make 
 it quick and easy for developers to build feature-rich and user-friendly interactive command line applications.  It 
@@ -61,6 +62,9 @@
 """.splitlines())))
 
 INSTALL_REQUIRES = ['pyparsing >= 2.0.1', 'pyperclip', 'six']
+if sys.platform.startswith('win'):
+    INSTALL_REQUIRES += 'pyreadline'
+
 # unittest.mock was added in Python 3.3.  mock is a backport of unittest.mock to all versions of Python
 TESTS_REQUIRE = ['mock', 'pytest']
 DOCS_REQUIRE = ['sphinx', 'sphinx_rtd_theme', 'pyparsing', 'pyperclip', 'six']

tests/test_cmd2.py

@@ -24,7 +24,7 @@
 
 
 def test_ver():
-    assert cmd2.__version__ == '0.7.8'
+    assert cmd2.__version__ == '0.7.9a'
 
 
 def test_empty_statement(base_app):