[obdgpslogger] Reading Error Codes

[Chunky Kibbles]

I put in some code to read error codes, finally. It took a massive
re-write of the parsing stuff in the code, which is why it took so long.

Please feel free to try it and let me know if you run into issues.. It
works with the codes output by my hardware sim, but I haven't tried it
in a non-CAN environment, or a real car yet.

Instructions:
1) Check out the latest version of the code from svn
2) Run obdgpslogger with the "-p" option
3) Enjoy tasty error code stuff at the bottom

Gary (-;