Fixed system compatibility handling
Added header conversion

Added a way to convert old headers into new ones.
Changed return type

Changed return type from list to tuple. Added error.log error check.
Unfortunately, if there is an error creating the error log, there is no
place to log said error...
Extended header conversion

Added a method for  converting new header files into old ones, if need
be. It will work with future headers so long as the BATTERY_STRING is
set properly in constants.py and the header conforms to header file
standards from firmware version 0.1 (F0).
Commented/cleaned code