Replace .iteritems() with six.iteritems() everywhere except in
module_utils (because there's no 'six' on the remote host).  And except
in lib/ansible/galaxy/data/metadata_template.j2, because I'm not sure
six is available there.

also updated extras to get some docfixes on the module side

now version_added < 1.3 does not get shown, up from 1.0
option's version_added is also now filterd against this threshold
module version_added is more prominent
exaples now uses pure rst instead of intermingled with html formatting
aliases now shown in description for options
bad version fields now throw warnings instead of exceptions
ansible-doc errors now show traceback in very very verbose mode, for easier debugging

now module_formatter handles new expanded return values from the module_docs (still does not thing with new return value docs)

now merge

something to show

documenting them. Soon will be patched to recognize them as either
deprecated or an alias

timeit shows a speedup of ~3x on Python 2.7.5 x86_64.
It also makes the code a bit shorter.

Add note about how to submit doc changes to generated module docs, limit TOC depth for module category list.