work on the docs
i think i finished adding stuff to the docs (usage.rst), now to test it..
tried to make the source code formatting work
Fixed double colons not having whitespace after them so the source code formatting was off
I think i fixed all of the rst errors, hopefully the :func: stuff works, cause it doesn't work on restview, only seems to work on readthedocs
Changed how format_validators are imported, since the already present function 'register_format_validator' wasn't even being used, i made it so that we go through the 'default' format validator dictionary and add those, and then we go through the user provided dictionary (if any) and register those, as before, if the user provided a format validator dictionary, then the default ones would be 'cleared' and not be able to be used.
Merge pull request #62 from mgrandi/mgrandi_master

Documentation improvements and fixes to user provided format_validators