Duck type img
return empty rect if container has no visible children
Dived into WebGLRenderer, fixes and docs
A nice getter/setter for our lovely users
Merge pull request #531 from alvinsight/dev

Dived into WebGLRenderer, fixes and docs
Reset Alpha for CanvasRenderer
Merge branch 'dev' of https://github.com/GoodBoyDigital/pixi.js into dev
replaced matrix
fixed render texture issue and jshinted code
Tweaked getLocalPosition

Also cahced css cursor reference in js
Merge branch 'dev-matrix' into dev
Tweaked tiling texture and jshinted code
Fixed type in bitmap font
Update README.md
fix typo in graphics webgl render
Protect against NaN rotation values

Throws an Error if a DisplayObject's rotation was set to NaN. Without this check, Sprite's textures could disappear silently, with no reference to the improper rotation value as the culprit.
Remove all references to mat3 or mat4
remove watch, we don't use it right now
Reusing children and use pool object.

When need update BitmapText very often it is not the best way  to create new Sprites and remove old.
So better way is reusing it and use pool object.
Merge pull request #539 from qzix13/dev

Reusing children and use pool object.