Fixes that achieve a working state on AMD hardware.
Replace glMemoryBarrier with a workaround for ATI/AMD cards instead of generally adding glFlush.
Seperate selection rendering from main simulation and fixing selection on AMD cards.
Fix selection rendering and comments.
Remove unnecessary clearing step.
Add single step mode for debugging purposes.
Fix performance issues with NVIDIA drivers.
Remove old shader tests.
Remove test directory from CMakeLists.txt.
More elaborate workaround for AMD/ATI glMemoryBarrier.
Fix typo.