Input keycodes used by the GUI:

1: Enter
2: Previous
3: Up (Prev)
4: Down (Next)
5: Page up
6: Page down
7: Louder
8: Silence
9: Play/Pause
10: Stop
11: Skip
12: Previous
13: Record
14: Record later
15: Shutdown

100: leave start screen
101: leave IR learn screen
102: leave file/station select screen
103: go to mp3 file play screen
104: go to stream play screen

(129: reserved for redrawing)

130: error1
131: info1
