Initial, basic analogRead() support.
Added support code for the ADC on the Gen2.
Fixed bug that Pin Mode could not be set to ANALOG_PULLUP.
Added/edited comments.
Moved code from SpiController.h to .cpp.
Added support for faster SPI speed (12.5 mhz) for ADC.
Added pin attributes table for Gen1.
Merge pull request #80 from JustAddWires/DMap

Initial, basic analogRead() support.