Remove the polarity protection diode and add a SPI SRAM device

This allows us to do on-chip DMA.
Add a 1/16th degree i2c TCN75A temperature sensor
Replace the TOAS sensor with a MAZeT True Color Sensor
Add a Microchip 6bit i2c DAC for future use
Add three test points to the PCB
Switch the LEDs to a multicomp RGB module