Updated PixiShader to use standard uniform naming conventions (1f, 2f, 2fv, etc). Added support for multiple sampler2D calls, allowing multi-texture shaders. Added support for Linear, Repeat, Nearest, Audio and Keyboard textures. Updated all the examples to use the new uniform naming convention. Updated Gruntfile to use the renamed GrayFilter and fixed indexAll in Example 15 to use the GrayFilter as well.
Fixed typo in AbstractFilter (unifroms to uniforms)
Made sampler2D check more robust.
adding base64 support to AssetLoader
cleaning up base texture destroy & adding removeAllEventListeners to EventTarget
Dramatically refactored PixiShader. Significantly smaller, less branching, much faster sync loop and no constant texture uploads.
Tweaking filters

Doc update
Merge branch 'pr/406' into dev

Conflicts:
	bin/pixi.dev.js
	bin/pixi.js
	src/pixi/renderers/webgl/PixiShader.js
Merged new PIXI Shader code
Fixed issue with removing children with filters
swapChildren basic implementation
simple swapChildren example/test
removed example from main swap branch
early-out for self-swap
check for invalid children
style consistency
Merge pull request #431 from namuol/swapChildren

`swapChildren` implementation
Fix setText documentation attribute
fix incorrect width property for multi-line BitmapText

BitmapText.updateText() was setting this.width to the width of the last line of multi-line text, rather than that of the longest line. this made it impossible to center multi-line strings. (found working in Phaser)
Merge pull request #415 from mattdesl/basetex-destroy2

Cleaning up BaseTexture Destroy