Switch to reStructuredText README

PyPI doesn't render markdown, it parses README.md assuming reST rules:
pypi/legacy#148
which currently causes joined lines on
https://pypi.python.org/pypi/manageiq-api-client-python/

Using README.rst with reST syntax is the simplest workaround.

Author: cben

README.md renamed to README.rst

@@ -7,18 +7,18 @@ This python package provides the ManageIQ API Client library.
 Getting Started
 ---------------
 
-Preparing your python virtual environment:
+Preparing your python virtual environment::
 
     $ virtualenv venv
     $ source venv/bin/activate
     $ pip install -e .  # To create an editable install of this package
 
-If you want to install it directly from GitHub:
+If you want to install it directly from GitHub::
 
     $ pip install git+https://github.com/ManageIQ/manageiq-api-client-python.git
 
 To run the example present in this repository you probably need to configure
-your options (if different from the default shown here):
+your options (if different from the default shown here)::
 
     $ export MIQURL=http://localhost:3000/api
     $ export MIQUSERNAME=admin