Tweak PWM heater output down

Add cruise control to MotorController (and in RMS driver)

Switch to nearest gear selection

Add an "ok to drive" flag to battery managers. Implement this in Tesla battery manager

Added components to library

Fixes to slow PWM in SysIO code

Require BMS for RMS controller. Disable the controller if BMS is faulted.

Minor corrections to potgearselector and the Tesla battery manager

Update the memcache interface to enable the write protect pin anytime we're not intenionally writing.

Add a PWM controlled heater device.