Rp1210

- Removed print statements that were left in the code by accident.
- Adjusted translateErrorCode() to better accommodate error codes reported as negative numbers.

- Added data_size param to toJ1939Message()
- Fixed ReadDirect() not parsing RxBuffer correctly in many cases

Recombobulated diagnostic messages:
- Added DTC class for parsing and generating diagnostic trouble codes
- Added DiagnosticMessage class for parsing and generating DM1, DM2, and DM12 messages

Added diagnostic message parsing:
- toDiagnosticData() function
- DTCParser class

Enhancements:
- Add RP1210VendorList to track all vendors specified in RP121032.ini
- Add RP1210Client (child of RP1210VendorList) to handle many command functions, clientID tracking, etc
- Add functions to J1939.py to check for diagnostic message PGNs

Other changes:
- Moved sanitize_msg_param() to init.py
- Pytest configuration changes
- More tests, extra push to improve code coverage
- ReadDirect() now returns b'' instead of a full buffer size of 0x00's when it doesn't receive anything
- Minor bugfixes

- Implemented more command generation functions in Commands.py
- Cleaned up sanitize_msg_param() a bit
- Add toJ1939Name() in J1939.py