Fix build for changes in Caustic.

Signed-off-by: Nick Minkler <sleaker@gmail.com>
Update for Caustic changes and fix GL20 mode

Signed-off-by: Aleksi Sapon <QcTechs@gmail.com>
Merge branch 'master' into new-math

Conflicts:
	src/main/java/org/spout/reactsandbox/Sandbox.java
	src/main/java/org/spout/reactsandbox/SandboxRenderer.java