Faster Array looping

Ok, so using the output buffer array for collision detection is a bad idea.
I'll try going back to an array of the fallen blocks to check for collisions.

@Gordon I get an error when I try to use m.buffer.set()

Uncaught Error: Field or method does not already exist, and can't create it on ArrayBuffer
 at line 1 col 13
mCopy.buffer.set(m.buffer);
             ^
 at line 1 col 9
m.buffer.set(mCopy.buffer);
         ^