Generalize blended animation for Object3D

Remove blend weight accumulators from THREE.Object3D - they have been moved to the animationCache object created by THREE.Animation.

Remove duplicated bounding box computation from the BufferGeometry

browserify Detector.js

Fixed editor animation breakage somehow.

browserify lzma.js and ctm.js,

THREE.CTMLoader.load : new option to manage workers outside the loader

This should "fix" all the problems of textures not rendering when the first instance of the geometry rendered didn't use.
Yet another premature optimisation that created a lot of confusion :(