Betterreads

- Fix broken restructured text that was breaking readme formatting on PyPi
- Update Readme with pip installation instructions
- Update contributing guide
- Add pull request template
- Remove unused requirement: nose
- Improve return types on goodreads interface classes (ex: datetime instead of date strings)
- Add requirement backporting 3.7 fromisoformat datetime function for 3.6 compatibility

- Fix auth to use https instead of http
- use code style black for python and code style prettier for other filetypes
- unit test suite with no live api calls, integration tests with minimal api calls
- minor fixes to some return types (returning GoodreadsGroup objects instead of dicts, for example)
- replace anemic GoodreadsShelf object with GoodreadsUserShelf - more robust data available
- xmltodict converts to dict object in GoodreadsRequest, rather than OrderedDict for easier debugging
- expanded documentation for each class
- Use pytest instead of nose