patches...

[Ed Sutter]

I pushed a few patches tonight...

1. Removed a few files from ports/beagleboneblack that were leftovers from csb740.
2. Added the code that initializes GPIO associated with the four LEDs and incorporated
   the uMon code that blinks a status led.

#2 was done primarily because I had done this when we were still debugging the boot-from-SD
code, and I figured it should be incorporated in.
Jarielle, if you decide later that the blinking LED is annoying, then just set
INCLUDE_BLINKLED to zero in config.h.

Ed