mchck.h: drop CMSIS include

CMSIS starts to collide with our own definitions, so drop it.
add SCB definition
toolchain: start system functions
mchck.mk: use SAT cpp to process the linker script
mchck.mk: target linker script is a dependency as well
toolchain: give the builtins their own header file
dfu: reset after successful download
Merge branch 'master' of github.com:corecode/mchck

Conflicts:
	toolchain/ld/MK20DX32VLF5.ld
use lower case for hex literals