Topside interface board: Expose 5V power and GND as solder points

To power the topside interface board from other sources than the USB port (for example for the community hack http://openrov.dozuki.com/Guide/How+to+build+a+USB-Ethernet+topside+adapter/54), the 5V power and GND lines should be exposed via solder points. This way people don't have to solder onto existing pins. 

This is probably a duplicate or replacement for #18.
