VectorTileMap is part of the OpenScienceMap project, developed at University of Bremen. 
http://www.opensciencemap.org

The android build system is not able to merge asset directories, 
(http://code.google.com/p/android/issues/detail?id=9042)
please copy:

cp -r ../vtm/assets/patterns assets/
cp -r ../vtm/assets/styles assets/