This starts the u-boot framework.
Changes are:
o grab u-boot from my github tree that has branches port-vYYYY.MM for each branch we support. All patches move to here so we can track things better.
o slim down the makefile and move most of the infrastructure goo into sysutils/u-boot-master
o upgrade to 2016.05 -- beaglebone done as PoC. All other omaps will be done next: pandaboard, duovero.