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/IGalTexture.cs

@@ -0,0 +1,13 @@
+namespace Ryujinx.Graphics.Gal
+{
+    public interface IGalTexture
+    {
+        void Create(long Key, byte[] Data, GalTexture Texture);
+
+        bool TryGetCachedTexture(long Key, long DataSize, out GalTexture Texture);
+
+        void Bind(long Key, int Index);
+
+        void SetSampler(GalTextureSampler Sampler);
+    }
+}