- added a centralized core implementation for all cortex CPUs
- moved default stack size defines to cpu.h in cortexm_common
- moved uart0 bufsize define to cpu.h in cortexm_common
- moved typed of panic_t to cpu.h in cortexm_common
- removed coretx-m[0|3|4]
- moved their content to cortexm_common
- adjusted cortex Makefiles to this new name
- adjusted cortex Makefiles new structure
- fixes to cortexm-common
- Added ARM CMSIS headers to cortexm_common
- thread_exit fixes to cortexm-common
- cortexm-common adjusted documentation
- cortexm_common added eINT dINT defines for now