Merge pull request #19 from playcanvas/master

merge
Fixed appearance of different blends, removed premultiplied blend from particles;
Fixed lifetime change weirdness, removed lifetime2;
Fixed alpha2 not working in CPU mode;
Fixed preWarm;
Fixed bug with color intensity multiplying alpha;
Particle gamma correction is now off when no lighting is enabled on particles;
Fixed possible error on dynamic 'lighting' parameter change;
Fixed system disappearing after changing oneShot a few times;
Fixed endTime calculation for oneShot emitters (didn't take rate2 into account).
Merge pull request #77 from guycalledfrank/particle-system-fixes-new

Particle system fixes (new)
Start rotation speed graph with -360, 360 as vertical axis values
Fixed some issues with particle system wrapBounds
Removed maxEmissionTime, Added descriptions to all particle system fields
Fixed some weird descriptions of components attributes
Fix some issues with sorting
CurveSet clone fix
[RELEASE] v01.159.1
[VERSION] v0.160.0-dev
curveset clone fix
Merge branch 'master' of github.com:playcanvas/engine
curveset clone fix
Merge pull request #20 from playcanvas/master

merge
fix: model component set asset to null on change type to non asset
Fixed particle system cloning.
Merge pull request #78 from guycalledfrank/particle-system-clone-fix

Particle system clone fix
Added crossOrigin property to TextureResourceHandler
Set to "anonymous" to enable cross origin texture loading.
Correctly initialise emitterScale