[FIX] mat4.getZ() no longer creates vec3 if one is supplied
[FIX] mat4.getZ() no longer creates vec3 if one is supplied

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