Added pc.math.log2, because Math.log2 is not supported on IE.
Added pc.math.log2, because Math.log2 is not supported on IE.

shinate/engine,nizihabi/engine,guycalledfrank/engine,MicroWorldwide/PlayCanvas,nizihabi/engine,SuperStarPL/engine,sanyaade-teachings/engine,3DGEOM/engine,playcanvas/engine,guycalledfrank/engine,MicroWorldwide/PlayCanvas,horryq/engine-1,sereepap2029/playcanvas,3DGEOM/engine,shinate/engine,sereepap2029/playcanvas,RainsSoft/engine,sereepap2029/playcanvas,SuperStarPL/engine,maxwellalive/engine,SuperStarPL/engine,sanyaade-teachings/engine,shinate/engine,H1Gdev/engine,playcanvas/engine,3DGEOM/engine,aidinabedi/playcanvas-engine,horryq/engine-1,maxwellalive/engine,RainsSoft/engine,RainsSoft/engine,sanyaade-teachings/engine,aidinabedi/playcanvas-engine,maxwellalive/engine,H1Gdev/engine,horryq/engine-1,nizihabi/engine