CortexM0: Add enum with bits describing ICSR
CortexM0: Implement interrupts driver
Merge branch 'master' into cortexm0-nvic

Conflicts:
	chaOS/mcus/cortex-m0/common/system_interrupts.h
	chaOS/mcus/cortex-m0/stm32f0/hw_interrupts.h
Merge branch 'master' into cortexm0-nvic

Conflicts:
	chaOS/mcus/cortex-m0/common/system_interrupts.h
add the M4 preprocessor to the toolchain (^^)
Merge branch 'master' into cortexm0-nvic

Conflicts:
	chaOS/mcus/cortex-m0/common/system_interrupts.h
	chaOS/mcus/cortex-m0/stm32f0/hw_interrupts.h
Merge branch 'cortexm0-nvic'