Updated CircularBuffer and UART code.

Previous code had a read/write conflict during interrupts.
Merge branch 'master' of https://github.com/xela144/CANaconda
Converts tabs to spaces.
Expand and correct the NMEA2000 messageset.
Added NMEA2000 messages 130312,130313,130314.

Messages are transmit by the WSO100.
Add PGN 128267.
Fix bug with newly-aded PGN128267
Fix extraneous whitespace, and spelling/grammar errors.
Refactor bounds on transmission fields.

Code is drastically simplified and is more Pythonic, using exceptions where it makes sense.
Remove debugging main()s from libraries.
Remove debugging print().
Move field bounds calculations to initialization.

Field bounds calculations can be done once when loading the metadata files, so we should just
do it then instead of everytime we need to check or use the bounds.
Merge pull request #46 from Susurrus/master

Firmware and metadata fixes