* Expose Java API to control discard flags
This change also adds the new sample sample-multi-view that shows
how to use discard flags to render multiple views.
* Disable clears
* Re-organize Android Gradle files
Clean up our Gradle files, share versioning, etc. and prepare for
publication to sonatype.
* Use androix annotations for desktop
* Add samples as subprojects to root Gradle
* Fix build script
* Don't break when samples aren't compiled
* Better organize the Android Studio project