Added CHDK support

Added so M240 can be used to trigger CHDK instead of sending an IR signal, see more about CHDK here http://captain-slow.dk/2014/03/09/3d-printing-timelapses/
Added CHDK support

Added CHDK support to take pictures instead of doing an IR command, see more about how to use it here http://captain-slow.dk/2014/03/09/3d-printing-timelapses/
Add support for disabling encoder control for feedrate multiplier

Signed-off-by: Matthew Schick <matthew.schick@gmail.com>
Individual extruder flow rate

Extension of M221, Tune menu