Fix errors in PCB found after initial testing.

 - Swapped pullup/down on RST/TEST lines (they were backward).
 - Added 4.7k pullups to i2c lines (maybe don't need but the signal is a little ugly without them)
 - Removed silkscreen of part numbers since they're not very readable anyway
Preliminary firmware for rev2 hardware.

 - Updated hw defs for new board
 - Added bitbanged i2c driver (USI on the g2452 was cumbersome)
 - Added tcs3414 light sensor driver
 - Initial code just reads clear channel for demo
 - Other minor tweaks