Add tests/gdx-tests-jogl

* tests/gdx-tests-jogl
	Add jogl tests based on gdx-tests-lwjgl

* backends/gdx-backend-jogl/src/com/badlogic/gdx/backends/jogl/JoglFiles.java
* backends/gdx-backend-jogl/src/com/badlogic/gdx/backends/jogl/JoglPreferences.java
	Updated to match the lwjgl backend code and
	updated to work with gdx-tests-jogl

Signed-off-by: Xerxes Rånby <xerxes@zafena.se>
Do load libgdx and lwjgl openal natives for the jogl 2 backend.

libgdx implements many low level functions natively thus calling
GdxNativesLoader.load() is mandatory.

libgdx uses lwjgl openal as its only primary audio backend, keep using it.

This change will enable startup of libgdx tests using the jogl 2 backend.

Signed-off-by: Xerxes Rånby <xerxes@zafena.se>
Merge pull request #1 from xranby/master

Add tests/gdx-tests-jogl