Instead of user defined symbols in assembly files or C files,
use linker scripts to add heap and stack - this is inconsistent
with ARM std linker scripts
--legacyalign, --no_legacyalign are deprecated from ARMC6 compiler, in order to
remove deprecated flags all linker files (GCC and IAR as well to have uniformity)
should strictly align to 8-byte boundary
SystemInit() was called condititionally, but necessary defines were not
set in mbed. Calling SystemInit() unconditional now.
Removed also conditiional calls to legacy CodeRed lib.