Fixed issue with masking not working with renderTextures / Filters

Masking for everyone, everywhere!
Removed this.local in InteractionData fixes #654
Tidied up json loader

Set ajaxRequest to be asynchronous
Added an error even back in
set alpha to false when setting color mask
AutoDetect now returns the canvas render in ie11
IE11 supports Stencil Buffer! Its back on the cards..

autoDetect will now return the webGL renderer in ie11 if available.
added PIXI.autoDetectRecommendedRenderer function
Merge branch 'dev-render-texture-masking' into dev
Merged texture mask branch

republished files
Merge branch 'dev' of https://github.com/GoodBoyDigital/pixi.js into dev