Bake in filters

Features:
    - Asset authors can include standard filters in Movie timelines
    - filters are parsed and propagated downstream, applied to XflTextures, and baked into texture atlases

Not supported:
    - tweening of filter parameters
    - Gradient Filters (just needs xml parsing code in XflKeyframe) 

Usage note:
    - Each XflTexture is rendered to the texture atlas with a specific set of filters associated with it. If the asset author wishes to reuse a leaf asset with different sets of filters on it, they can create separate symbols wrapping each filter configuration.

Development note:
    - The parsing of the AdjustColorFilter introduces an external dependency to fl.motion.AdjustColor.  This, in turn, requires fl.motion.ColorMatrix and fl.motion.DynamicMatrix.  These files are sourced from the Flash CS Distribution as as3 files or as flash.swc.  The as3 files contain no copyright notice, but I have not included them in this pull request.  Please let me know if you would like assistance with obtaining them.