Make GSM communication a lot more robust

[amcgee]

Well that was fun....

• Update gsm board to fix issues
• Recognize roaming registration as well as local registration
• Fix initialization order for syslog
• Implement unit testing for gsm module
• Reclock down to 19200 baud so we don't miss characters
• Implement buffer and gsm_rx logic in assembly
• Update linear address space to not conflict with other variables
• Diagnoze and work around the most terrible XC8 compiler bug in the whole world
• Detect GSM band and attempt to optimistically select it for subsequent registrations
• Implement MoMo controller UUID storage, include that UUID in reports, and also timestamp each report explicitly
• Move all gsm logic to interrupt code to avoid annoying XC8 bugs
• Support HTTPS
• Give later report streams precedence so we can't hang forever

[amcgee]

This is almost ready, but I'm investigating a buffer issue that appears to be related to shared interrupt and mainline code routines.

[amcgee]

This is ready for review.