Add LED zones for multi-player support

[Gadgetoid]

This is a suggested alternative to #13 which has been conflicted beyond rescue.

1. A zones section in plasma.conf where you can set a name with an offset + count
2. hoist all the daemon's state out of main into per-zone state
3. add some way to specify zone in the pipe protocol
4. --zone in plasmactl

Instead of two daemons, it becomes plasmactl --zone player1 and plasmactl --zone player1 with the single daemon mapping all LEDs connected to the board, and the zone config deciding which player (or other feature, such as pulsing status LEDs, underlights, etc) controls which lights.