Volttemp + Amperes Refactor

[tiandahuang]

Major refactor of Volttemp and Amperes tasks. This includes:

• Tasks rewritten for clarity. Task functionality abstracted out to various (small) helper functions
• Functions from Voltage.c, Temperature.c, and Amps.c updated for more consistent return types (and more information)
• Functions in tasks and apps optimized for better performance (fewer unnecessary loops!)
• Fixed logic associated with temperature (charge disable message was an impossible condition) and added new cold temperature charge/discharge limits in accordance with regs.
• Added support for reducing Voltage Array, Temperature Array, Current, and State of Charge CANBus message data rates with an adjustable period.
• Added 2 new CANBus messages, Voltage Summary and Temperature Summary containing brief information about pack voltage/temperature.

[tiandahuang]

note: this ain't tested on real hardware yet; will update accordingly once properly validated.