Remove unused definition
MRI-Binding: Don't memcpy script data before deflating

I think the reason this was originally done was some
issue with ruby's GC where it would wrongfully sweep
the script array variable on the C stack.

This change should speed up startup a little.
mkxp.pro: Shorten keyword lenght to choose binding

'BINDING=BINDING_MRI' => 'BINDING=MRI'

Also error out if multiple bindings are chosen.
Exception: Constructor now takes printf style arguments