testing tile overlay
tile overlay experiments II
Merge branch 'master' of git@city.informatik.uni-bremen.de:vtm-android.git into tile_overlay
added MapLensOverlay
-use absolute x/y position and scale in MapPosition
 - scale calculations look much nicer now, better always
   use 'double' unless you are sure about precision required
- finally got rid of zoomLevel relative coordinates
- cleanup MapPosition and MercatorProjection API functions
rename Tile.TILE_SIZE to Tile.SIZE, while I'm at refactoring
theme: brighter swimming pool
moved to backup