Add control program file:
- Can be used to send a time initialization message to the mbed
Add install program:
- Install programs on both mbeds and initialize the time on one
Add IRQ driven serial interface:
- Since we don't have spare DMA controllers available for this
homework we need to transmit serial data some other way.
- The IRQ code allows us to queue up large messages to be transmitted
asynchronous to main background loop. It should also help with
receiving data at a high rate.
Add task table to main:
- This lets us schedule tasks at fixed intervals.
Fix various bugs:
- Timer dma code reset avoid config errors cause by periodical request
while the DMA controller has nothing to transmit.