Unit Tests: Group *math* tests in own test package
ScreenMode Unit Tests: Add wait for screen destroy (off-thread)
Bug 747: Allow usage of IdentityHashMap w/ keys: AbstractGraphicsDevice.getUniqueID() and GLContext.getDeviceVersionAvailableKey()

.. both value classes unique, long lived and rare.
Adapt to Gluegen's IOUtil change commit b98825eb7cfb61aead4a7dff57471cd2d2c26823