enable hacking.py self tests

pep8 and hacking.py (by inheritance) have the ability to run self
tests via docstrings, if we format the comments correctly, and change
the docstring test regex. Include self testing in our normal pep8
tests.

fix the comments to actually be test case compliant

fix nova_import_alphabetical to pass on short import lists (only 2
lines, starting at the beginning of a file)

comment where it doesn't appear that hacking.py tests are working
(though there could be deeper black magic in some of them).

fix a doc string in pep8 self tests that breaks N301

fix the fact that pep8 error strings are supposed to start with
\w\d\d\d, we were just lucking out on some formatting because the
string NOVA happened to be only 4 chars long.

Add a couple of escapes so that we don't recursively fail on our
own fail self tests for comments. (boy that's fun)

Change-Id: I14d5e04cfc092b37ec4967cd7485e9975a5eb820
Merge "enable hacking.py self tests"