OpenOCD config
Bypass oscillator circuit and take external clock directly.
Addresses added in startup code and verified.
switchToHse implented, all clock functions tested in hardware.
Typo.
HSI disabled.
Merge branch 'feature/stm32_f3_support' into feature/uart_hal

Conflicts:
	src/xpcc/architecture/platform/cortex_m3/stm32/stm32f3/clock.cpp
Const param in clock
Merge branch 'feature/uart_hal' of github.com:roboterclubaachen/xpcc into feature/uart_hal