cpu: Initial import of stm32f3
board: Initial import of stm32f3discovery
cpu - cortex-m4_common: fixes to thread_arch.c
examples/tests: blacklisted stm32f3discovery
Merge pull request #1456 from haukepetersen/board_stm32f3discovery

board/cpu: Added support for the stm32f3discovery board and stm32f3 cpu