Aprs

- added util submodule containing various helper functions
- added objects for creating packets (PositionReport, APRSPacket in packets submodule)
- added DAO parsing
- added parsing for invalid & user-defined formats
- split parsing module into submodules
- fix rounding error in base91.from_decimal
- added py35, pypy, pypy3 to travis
- fix exception due to EUC-TW encoding, 11
- added parsing for WX (positionless and in comment)

LOTS OF MINOR STUFF

- charset detection, unicode for all
- improved _parse_timestamp
- fix mic-e dstcall decoding bug
- tiny syntax fix in parse.py

- fix typo in timestamp format
- tweak debug messages for position reports
- now able to parse object report format

- rotated base91 telemetry bits in output

- fixed timestamps being parsed incorrectly

- added ambiguity parsing for normal position reports
(fixes the unexpected exception)