Added support for Texture2DArray to ShaderGenerator.
Made createImage in SkinResource public.
Added ExtrudeGeometryArrayFilter to use texture arrays when generating buildings to speed things up.
Moved SkinTextureArray into the Skins file.
Merge branch 'topic-building-texturearrays'
Added ExtrudeGeometryTexArrayFilter to CMake.
Moved SkinTextureArray cache and ResourceLibraryCache to the ResourceCache.
Merged texture array logic into ExtrudeGeometryFilter
Merge branch 'master' of https://github.com/gwaldron/osgearth