Code Merge Request #3: add OpenSLES audio driver for Android support (rejected)

This change adds supprot for Android OpenSLES driver.

Android fluidsynth build is somewhat tricky, especially fluidsynth requires glib-2.0, so I created a builder repo that makes use of cerbero build system (which is used by gstreamer project).
https://github.com/atsushieno/android-fluidsynth

(There is no JNI suppot. I use it just with Android NDK + Xamarin.Android which doesn't require any additional C/C++ component.)

[Tom M.]

Nice work. However your github fork seems to be more up to date. Since we also moved to github, feel free to submit another PR there.