Correct alignment issue in GCC Cortex-R port that was preventing full floating point usage in interrupts (other ports will be updated likewise).
Update the UltraScale R5 demo to test the GCC Cortex-A9 port layer modification mentioned on the line above.
+ Add the pre-existing 64-bit Cortex-A53 port layer into the head revision of the main repository.
Demo application updates:
+ Update Zynq demo to use SDK version 2015.4
+ Add task static allocation standard demo to Zynq demo.
+ Make the XScuGic object accessible outside of the vConfigureTickInterrupt(), again in the Zynq demo.
