Assets 2
I'm dropping Android support for a number of resaons:

 - It appears that OpenGL and OpenGL ES are not as compatible
   as they should be. Not only do they have slight (annoying)
   differences in the shading lanaguages, but the features
   available are wildly different.

 - I'd like to investigate a deferred rendering, but the
   versions of OpenGL ES commonly available on Android don't
   have the nessasary features to support deferred rendering.

 - I don't want to write and maintain two rendering engines.

 - The Android port has always been quite buggy.

 - The controls were never properly sorted out.

 - Performance is much wors than the PC versions. A better
   written game, or one designed for mobile would not suffer
   from these issues.

 - I'd like to add more content (maps, items, sounds, music)
   but space is a much bigger issue on mobile.

 - Very little support for this port. Only a handful of
   downloads. Google play says 50 to 100, and it's been up
   for about a year.

 - If I'm going to get back into game development, I want to
   spend my time on the *game*, not on debugging platform issues.

I am tagging the commit, as it can be used (if ever desired) as
a basis where an future cross-platform or Android-only version
of the game can be based.

Also, if I ever port the game from OpenGL to Vulkan, and if the
hype is to be believed (i.e. same API and similar perf across
platforms), then I may re-create the Android port some time in
the future.