Revamp the way external memory regions are configured; Add logic to add SAMA5 external memory regions to the heap

Improve some ARMv7-A/M floating point register save time; Add floating point register save logic for ARMv7-A

ARMv7-A:  Need 8-byte stack alignment when callign C code from interrupt handlers.  This change needs to be ported to other ARM architectures as well

SAMA5 clock configuration should now agree with Atmel sample code; Added header file with macros to enable and disable peripheral clocking

Add a general bit-bang SPI lower-half driver and implement the bit-bang driver for the Arduino ITEAD TFT shield

Add an NSH configuration for the Arduino Due; Pluse several fixes related to the Due and to the SAM3X in general

Flesh out the Arduino Due board configuratino and integrate it with the build and configuration system

Add peripheral configuration logic for the SAM3X/3A; Change all references to SAM3/4 SPI to SPI0 for compatibity with the SAM3X/3A which has SPI0 and SPI1; Add directory which will eventually holdl an Arduino Due port

Add support for a separate CCM memory allocator for members of the STM32 family that support CCM memory

Fix UG-2832HSWEG04 landscape.  Add reverse landscape support to UG_2864AMBAG01 and UG-9964HSWAG01.  Fixe NXHELLO default colors for 1-bit mono modes

Add support for the UG-2843HHSWEG04 OLED and for the SAM4L Xplained Pro OLED module that uses that OLED.