Small OpenGL Renderer refactoring (#177)

* 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

Ryujinx.Graphics/Gal/Shader/GlslDecl.cs

@@ -26,6 +26,8 @@ namespace Ryujinx.Graphics.Gal.Shader
 
         public const string FragmentOutputName = "FragColor";
 
+        public const string FlipUniformName = "flip";
+
         private string[] StagePrefixes = new string[] { "vp", "tcp", "tep", "gp", "fp" };
 
         private string StagePrefix;