Using "SDL2/SDL_xxx.h" instead of "SDL_xxx.h" caused
the include paths provided by pkg-config to be ignored,
and headers from a standard include path to be used instead.
A compiled ".mrb" script can be specified in the Binding config
subgroup with key 'mrbFile='.
If a 'customScript' is specified it still takes priority however.
time_op now takes 2 optional arguments:
iterations: block will be run this many times and the average
time it took will be printed
opName: tag that is printed before the measured time
Also returns the measured time as float.
I also removed the 'MKXP' module because it was clashing with
the likewise named global const.