Since #1047 was merged, we now make the user build the SDL prefab
themselves (as SDL does not publish Maven packages yet). Here are some
instructions for doing that.
This serves as a file to help others in building the C++ Android version
for themselves.
These instructions are what I figured out to get it to work for me, and
should be kept up to date.
This is somewhat convenient for development, as it means that Android
Studio will only do a native build for the architecture of the device
being used for testing.
This is ignored for AABs, so it won't affect release builds (at least
for Google Play).
