Add more gl extensions and spacing
Enhance 'time_op' and remove unused test code

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.
Fix compile error
'time_op': print empty string instead of "(null)"
Minor cleanups and documentation