bring vtm-android-gdx back to life
fixup: area fade
wip: StyleBuilder
fix: AreaStyle blend
android-example: reenable cache..
PolygonBucket: enable fade and tinting of textured polygons
add Color.isOpaque util
ExtrusionLayer: animate when loaded
pass fx option with S3DBLayer constructor
updated default theme:

- use textures for slight roughness of 'natural' features
- increase font size
fix: show tiles at the highest scale

need to investigate the real cause..