* Connect input header CV/GATE rails to the bus, this makes it possible
to chain boards into the same bus using the existing headers on the
output header.
* Move the via's for the +12V rail to the tile power connections so it
doesn't cross most of the GND signal path on the top ground plane.
Remove one of the tile power headers then move the remaining ones to
interleave with the Eurorack power headers, this simplifies the +/-12V
routing.
Add indicator LEDs for the +/-12V and +5V rails.
Power distribution for 5 shrouded Eurorack power headers and 5 1u tile
power solder points. Layout is left to right, this may not be the most
optimal orientation.
