Remove the Microchip project files as they are unused
Add support for the Microchip TCN75A to get the ambient temperature
Add commands to read and write from the SRAM
Increase the device frequency to 24 Mhz

Also, because of a typo, rescale the delays to reality.
trivial: Fix up an incorrect gtk-doc tag
trivial: Remove code to support anything other than 18F46J50
trivial: Clarify the RCx pin descriptions
trivial: Some more 'unsigned char' -> 'uint8_t' type changes
Add support for setting and getting the DAC value