Atlas: new ExtrudeGeometryFilter work
ResourceCache: cache skins by their URI only for better resource sharing.
Art updates - better looking rooflines
LineSymbol: added stroke-crease-angle for outlining control
Art updates.
LevelDBCache: debug messages update
Clean cruft
ShadowCaster: default to 4096 texture size!
ExtrudeGeometryFilter: fix texturing bug in final polygon segment
Atlas: add support for creating auxiliary atlases
Code cleanup.
Merge branch 'topic-atlas'