Add information about the Google style guide

Many of these checks came from the Google Style Guide, which has
excellent reasoning and background. Add links so that people can read
more about things that they may think are crazy.

Change-Id: I18f8250374ee3b2132ed56be21c7e3eecb60771d

HACKING.rst

@@ -1,11 +1,10 @@
-OpenStack Style Commandments
+OpenStack Style Guidelines
-============================
+==========================
 
 - Step 1: Read http://www.python.org/dev/peps/pep-0008/
 - Step 2: Read http://www.python.org/dev/peps/pep-0008/ again
 - Step 3: Read on
 
-
 General
 -------
 - Put two newlines between top-level code (funcs, classes, etc)
@@ -320,3 +319,8 @@ and how to split up commits into a series of changes, consult the
 project wiki:
 
    https://wiki.openstack.org/GitCommitMessages
+
+Futher Reading
+--------------
+
+  http://google-styleguide.googlecode.com/svn/trunk/pyguide.html

README.rst

@@ -3,6 +3,16 @@ Introduction
 
 hacking is a set of flake8 plugins that test and enforce the OpenStack Style Commandments, `HACKING.rst <HACKING.rst>`_.
 
+Origin
+======
+
+Most of the additional style guidelines that OpenStack has taken on came from
+the Google Python Style Guide.
+
+  http://google-styleguide.googlecode.com/svn/trunk/pyguide.html
+
+Since then, a few more OpenStack specific ones have been added or modified.
+
 
 Versioning
 ==========