Pipup

- Fixed missing MANIFEST.in file (thanks to Tim Hatch)

- Removed unnecessary requirements
- Removed "copy to clipboard" feature that only works on OSX
- Upgrade to Click 7
- Fixed argument case inconsistency between pip and pipup
- Updated setup and PyPI description
- Added tests

- Fix unhelpful error message when pipup can't find your requirements.txt file. Thanks Melissa Hill for finding and reporting the bug

- Initial version