Sparky: enable ADC driver

This sets up the pin mappings (defaulted to two pins) and initializes
the driver.
Sparky: disable last two output channels when ADC enabled

This needs to move into a configuration option and select
either PWM or PWM+ADC.
Sparky: enable battery module (and comusbbridge)
Merge pull request #568 from peabody124/sparky_adc

Sparky: enable ADC pins