pypa/pip — pull request #1464 by qwcode (2014-01-12 18:14:57+00:00)
Title: break up req.py into a package

this breaks `req.py` into a package like so:

```
req/
__init__.py # has an __all__ that preserves major imports
req_set.py # main item: RequirementSet
req_file.py # main item: parse_requirements
req_install.py # main item: InstallRequirement
req_uninstall.py # main item: UninstallPathSet
```