STM32F3: Startup: Reenable GPIO pins
STM32F3: CLOCK: Read out reserved values.
Merge branch 'feature/stm32_f3_support' of https://github.com/roboterclubaachen/xpcc into feature/stm32_f3_support
Merge branch 'feature/stm32_f3_support' into feature/stm32_timer_motor_control