Analytics-python

- fixing requirements.txt

- adding versioned requirements.txt file

- Adding fixes for handling invalid json types
- Fixing byte/bytearray handling
- Adding `logging.DEBUG` fix for `setLevel`
- Support HTTP keep-alive using a Session connection pool
- Suppport universal wheels
- adding .sentAt
- make it really testable
- fixing overflow test
- removing .io's
- Update README.md
- spacing

- adding top level send option

- fixing debug logging levels

- fixing unicode handling, for write_key and events
- adding six to requirements.txt and install scripts