cpu: added enableIRG implementation to cpu/lpc1768
hwtimer: clean up of interfaces to board/cpu
Merge pull request #919 from haukepetersen/hwtimer_cleanup

core/cpu: renamed ARCH_MAXTIMERS to HWTIMER_MAXTIMERS
Merge pull request #923 from haukepetersen/mbed_enableIRQ

cpu: added enableIRQ implementation to cpu/lpc1768
tests/pkg: fixed issues from #919
Initial import of low-level GPIO driver interface
Fixed spelling errors
Merge pull request #612 from haukepetersen/periph_driver_gpio

Initial import of low-level GPIO driver interface
Merge pull request #929 from haukepetersen/hwtimer_cleanup_fix

tests/pkg: fixed issues from #919
Initial import of low-level timer driver interface
Initial import of low-level UART driver interface
Fixed spelling
drivers: remodeled low-level uart driver interface

- added blocking mode of operation
- added UNDEFINED device for compatibility
- changed baudrate type to uint32_t
cpu: added cortexm common
core/cpu/board: moved F_CPU define to board
core: changed e|dINT calls to en|disableIRQ
core: changed e|dINT to en|disableIRQ in hwtimer.c
Introduced a cleaned-up cpu/core interface

- Included a collection of cpu-dependent headers in core/include/arch
- Extracted all interfaces that need to be implemented for a cpu
- Created a mapping between those interfaces and the old ones

Conflicts:
	core/include/lpm.h
core: added flag for disabling arch interface
core: added missing state to lpm_arch interface