SAM3X/Arduino Due: Fix typo in sam3x_periphclks.h; add SCLK definitions to board.h header file.  From Fabien Comte

SAM3X/Arduino Due: Fix typo in sam3x_periphclks.h; add SCLK definitions to board.h header file.  From Fabien Comte

Remove the 16z board support from the main source tree.  It is still avaialable in the misc/Obsoleted directory

Obsolete support for the 8051 family.  Trying to maintain compatibility with this family is too much effort and there has never really been a successful NuttX impplementation on these parts

SAMA5D4-EK:  Add a configuration for testing the kernel build configuration (still a work in progress)

Separate flat, protected, and kernel mode library selected into separate files.  The conditional logic as exceed my able to comprehend and maintain the selections.

Various changes/fixes to get configs/stm32f4discovery/kostest working after the big configuration renaming (and after a long period of bit rot)

STM32 FLASH fixes: use size_t instead of uint16_t, make interface more generic.  From Freddie Chopin