Model Requirements, Provides, and Obsoletes in the database
Pull the requires, provides, and obsoletes from PyPI and persist it
Handle the deprecrated requires like fields
Resolve a mistaken in instead of =
Properly handle extracting requirements from setuptools

* Looks for a *.egg-info/requires.txt and parses it into PEP345
  like metadata
* Attempts to make sure that "Hard" (e.g. from PEP345) requirements
  always win out over "approximate" (e.g. from setuptools)
  requirements
Don't use INNER JOIN to handle the requirements

Apparently there is some error from attempting to use inner join
for requirements/provides/obsoletes. Switching to SQLA's normal
join works fine.
Fix PyLint errors
Merge pull request #24 from dstufft/store-requirements

Store Requires/Provides/Obsoletes