Work in progress: properly reload asset files if they have changed
Fixed subscribing to texture's change event multiple times, Fixed cubemap loading
Cleanup
Cubemaps now reload images if referenced textures are reloaded
Updated call to TextureResourceHandler constructor
Fix loading of images by url only for cubemaps
Check if asset data properties are undefined before setting them to new textures
Added asset#set method and using that to fire 'change' events
Handle model reloading when a new model overwrites the old one, Cleanup
Added comment
Reload animations when they are overwritten
Do not create multiple promises when loading texture and cubemap parameters
First remove from cache and then unregister hash
Added documentation for particlesystem component.
Old particle system was deleted.
Removed 2 from ParticleEmitter2/particle2.
depthTest renamed to depthWrite in particles (that's what it actually does).
Removed unneeded code from simulation.
Fixed flickering bug when using CPU wrapping.
Yet another particle gamma correction fix + replaced old unnecessary slow code.
Remove requestAnimationFrame polyfill since browser support is now at 100%
Merge pull request #122 from playcanvas/feature/remove-raf-polyfill

Remove requestAnimationFrame polyfill since browser support is now at 10...
Merge pull request #121 from guycalledfrank/particle-system-docs-fixes

Particle system docs & fixes
Removed unnecessary function argument
Properly reject cubemap resource if an error occurs while loading images, Pass null when resolving without sources