GPS Locking Bug

Under certain circumstances GPS could lock up if antenna wasn't screwed
on correctly and it had gone into PSM mode. Added code to put it back
into max performance mode and eventually cold boot the GPS if having
issues.

Also added additional error bit 2 indicating an issue with temp sensor.
Fixed warning LED blinking warning (now blinks at 1hz as expected when
there is an error condition)
Added battery voltage to telemetry
Change status code to hex
Changed default call sign to CHANGEME
Removed some redundant variables