Pocket Edition v0.16.0 alpha build 3

v0.16.0 alpha build 3 (labelled v0.15.90 alpha build 1 in-game and 0.15.90.2 internally) is the third build version released for v0.16.0, also known as the Boss Update.

VR bug fixes in this update were later added to v0.15.10.

Fixes

 * Others
 * Removed placeholder art