Initial revision F

Changes:
* Removed Atmega8 + second RS485 interface, because we're using an RS485 hub and RDM instead
* Added more (software controlled) status LEDs
* Added optional external VCC for the relais drivers
* Replaced SMD solder jumpers with real jumpers for DMX Term / Pull Up / Pull Down
* All components placed now on the first layer, in order to allow reflowing of the components