Fix for various Android build errors. Enable landscape rotation.

  * Fix typo in Android Makefile ndk path. #1678  
  * Fix Makefile not checking leveldb.
  * Fix touchscreen parts of game.cpp to work after Zeno's refactor.
  * Fix isdigit and isspace overload conflict with Android Irrlicht in string.h
  * Enable sensor landscape rotation in Android Manifiest.
  * Add mapgen v5 to Android build.