* Implement stencil testing
* Implement depth testing
* Implement face culling
* Implement front face
* Comparison functions now take OGL enums too
* Fix front facing when flipping was used
* Add depth and stencil clear values
* Call OpenGL functions directly, remove the pfifo thread, some refactoring
* Fix PerformanceStatistics calculating the wrong host fps, remove wait event on PFIFO as this wasn't exactly was causing the freezes (may replace with an exception later)
* Organized the Gpu folder a bit more, renamed a few things, address PR feedback
* Make PerformanceStatistics thread safe
* Remove unused constant
* Use unlimited update rate for better pref
* Initial implementation of the texture cache
* Cache vertex and index data aswell, some cleanup
* Improve handling of the cache by storing cached ranges on a list for each page
* Delete old data from the caches automatically, ensure that the cache is cleaned when the mapping/size changes, and some general cleanup
