Hoppie-connector

Added new message types, alongside general improvements to code quality.

* Reworked ADS-C message handling
* Added ADS-C contract request messages
* Added ADS-C periodic contract cancellation and rejection messages
* Added CPDLC messages

**Full Changelog**: https://github.com/islandcontroller/hoppie-connector/compare/v0.1.0...v0.2.0

A basic working implementation, subject to further development.

- Message retrieval via `peek` or `poll` requests
- Station `ping`-requests, including online station list retrieval
- Server response time reporting
- Parsing of received ADS-C messages
- Parsing and sending of TELEX messages
- Parsing and sending of OOOI Progress Reports

Early working prototype. Tests deployment to PyPi