Add STM32F4 Discovery board examples to configuration GUI.
Add STM32F4 Discovery board examples to configuration GUI.

ambrop72/aprinter,ambrop72/aprinter,fixator/aprinter,fixator/aprinter,fixator/aprinter,johnkingsley/aprinter,johnkingsley/aprinter,johnkingsley/aprinter,ambrop72/aprinter,fixator/aprinter,ambrop72/aprinter,johnkingsley/aprinter,johnkingsley/aprinter,fixator/aprinter,johnkingsley/aprinter,ambrop72/aprinter,ambrop72/aprinter,fixator/aprinter,ambrop72/aprinter,johnkingsley/aprinter