Updates to README files
Move SAM3U header files to arch/arm/src/sam3u/chip. Some renaming of SAM3U to SAM to ssupport SAM4.  Convert all configs/sam3u-ek configurations to use the kconfig-frontends tool
Eliminated sam3u_internal.h. Use separate header files instead.  More renaming from sam3u_ to sam_ to make room in the namespce for the sam4l_
Add missing NSH configuration settings.  Correct some conditional logic for STM32 FALSH pre-fetch settings.  From Lorenz Meier
Rename sam3u/ architecture directories to sam34/ to include the SAM4L
Add dprintf() and vdprintf()
Fix an assertion
Add interrupt and memory map definitions for the AT91SAM4L
Add vector and chip cability definitions for the SAM4L family
Add a skeleton configuration that will eventually support the SAM4L Xplained Pro board
SAM4L alternate pin mapping header file; Use USART1 for virtual COM port console
NxWidgets::CImage: Allow NULL bitmaps.  From Petteri Aimonen
Change auto-increment timing in NxWidgets::CNumericEdit.  From Petteri Aimonen
NxWM::CTaskbar:  Add a method to redraw the task bar and the top application.  From Petteri Aimonen
Add stm32_dmacapable interface to determine is it is possible to perform DMA from a given address.
If CONFIG_STM32_DMACAPABLE is defined, use stm32_dmacapable to workaround attempt SPI DMAs from the CCM stack
Add SAM4L (and 4S) GPIO register definitions
Create SAM4L GPIO driver header file
Add SAM4L GPIO driver
More changes that should have gone with the last commit