Merge pull request #11 from playcanvas/master

merge
Velocities are now primary way to specify particle motions. Offsets are removed. Simulation works differently. Internal data layout changed.
Divergence now specified as 2 curves with random point between them. So the formula is lerp(param, param2, random).
rate and lifetime can be randomized
added startAngle parameter
faster stretching
speedDivs are removed
fixed NPOT particle count bugs
fixed particle spawn positions to match respawn positions (original spawn pos ignored emitter rotation)
dynamic change of oneShot behaves differently (not fully correct but less buggy)
particle random seed now changes after each new emission

This version doesn't work on iPhone or something else low on uniforms. I'll commit a fix ASAP.
fixed default curve keys in schema
added default texture (1x1 white)
Detecting low uniform count and switching to fallback;
Fancier default particle texture
Merge pull request #67 from guycalledfrank/particle-system-big-update

Particle system big update