cmd_setfont fail

[jamesbowman]

cmd_setfont does not work on Arduino (or any 16-bit host) because of varargs:

https://github.com/jamesbowman/gd2-lib/blob/master/GD2.cpp#L637

Best solution is to rewrite all commands to avoid fmtcmd.

[jamesbowman]

Fix confirmed. Closing.