BeagleBone/PrussDemoSubmission

Design
Using the PRUSS functionality of AM335x core for driving an vacuum fluorescent display using a shift register in realtime.

This proposal will have the following:


 * Having PRU control everything once loaded
 * Multiple PRU cores utilized.
 * Example will have be one driving the display and another incrementing the clock (in seconds).
 * Userspace can also talk to the PRUSS to update data in almost real time.
 * Explaining why SPI transfers, and GPIO bit banging doesn't work with applications like these.