pep8: fixed multiple violations

Fixed violations:
* E128 continuation line under-indented for visual indent
* E251 unexpected spaces around keyword / parameter equals
* E265 block comment should start with '# '
* E713 test for membership should be 'not in'
* F402 import shadowed by loop variable
* H305  imports not grouped correctly
* H307  like imports should be grouped together'
* H402  one line docstring needs punctuation'
* H703  Multiple positional placeholders

Also enabled H803 check that didn't have any violations.

Change-Id: I957ab273ddc61b02763d6b60b21d11ed4e73d472

colorizer.py

@@ -42,11 +42,11 @@
 """Display a subunit stream through a colorized unittest test runner."""
 
 import heapq
-import subunit
 import sys
 import unittest
 
 import six
+import subunit
 import testtools