Fixed TilingSprite not render children on canvas

TilingSprite does not render children on 2d canvas. The call to
children's renderCanvas method is missing.
Fix Text.destroy() and fix memory leak in BaseTexture.destroy() if basetexture was from canvas
Implemented animationSpeed for Spine animations.
Default value is 1.
This is simply the "timeScale" value from the Spine runtime, but with a more friendly name.
Add scaleMode params to FilterTexture and RenderTexture
Added support for dropShadowColor.

Initial support for colouring of drop shadows on PIXI.Text();
Merge pull request #668 from TomSlezakowski/dev

Added support for dropShadowColor.
Fixed prototype of DotScreenFilter
Json Loader tweaked to use XDomainRequest for ie9
Merge branch 'dev' of https://github.com/GoodBoyDigital/pixi.js into dev
Merge pull request #669 from schultka/patch-1

Fixed prototype of DotScreenFilter
Fixes #637 alpha mont being applied correctly to cachedAsBitmap Sprite

republished files
Merge branch 'dev' of https://github.com/GoodBoyDigital/pixi.js into dev
Generated Docs
Updated pixie version to 1.5.2
Tweaked CacheAsBitmapExample

fixed anchor point issue with cacheAsBitmap
Fixed texture loading on IE11
Fixed Data URI loading
Better solution for Data URI crossorigin
Merge pull request #680 from ekelokorpi/dev

Fixed texture loading on IE11
Added multitouch support