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>