documentation Updated README.md for module release

Updated the README.md documentation in anticipation
of the puppet-quantum 2.0 release (Grizzly). Matched
style to other modules, added a short example, and
included links to further documentation and resources.

* Added example code to enable quantum networking in nova.
* Included a list of other quantum network drivers of
interest.
* Updated contributors to point to the latest github
graph.
* Trailing whitespace removed.
* Added cisco-quantum to documentation
* backticks around inline source

Change-Id: Ice968a719541c8e3a8924647690a99ef6d304378
Merge "documentation Updated README.md for module release"