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.HLE/Gpu/Engines/NvGpuEngine2dReg.cs

@@ -0,0 +1,25 @@
+namespace Ryujinx.HLE.Gpu.Engines
+{
+    enum NvGpuEngine2dReg
+    {
+        DstFormat          = 0x80,
+        DstLinear          = 0x81,
+        DstBlockDimensions = 0x82,
+        DstDepth           = 0x83,
+        DstLayer           = 0x84,
+        DstPitch           = 0x85,
+        DstWidth           = 0x86,
+        DstHeight          = 0x87,
+        DstAddress         = 0x88,
+        SrcFormat          = 0x8c,
+        SrcLinear          = 0x8d,
+        SrcBlockDimensions = 0x8e,
+        SrcDepth           = 0x8f,
+        SrcLayer           = 0x90,
+        SrcPitch           = 0x91,
+        SrcWidth           = 0x92,
+        SrcHeight          = 0x93,
+        SrcAddress         = 0x94,
+        CopyOperation      = 0xab
+    }
+}