add additional pins to flatband connector

[mariolukas]

for more polygon mirror support add additional pins to the flatband connector. some GND and VCC pins are redundant

[cemonds]

We need the following pins:

• laser VCC
• laser GND
• laser detector VCC
• laser detector TRIGGER
• polygon mirror VCC
• polygon mirror GND
• polygon mirror ENABLE
• polygon mirror CLOCK

Am i missing something? Perhaps we should include some spare pins for other needs?