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/NvGpuEngineDmaReg.cs

@@ -1,22 +0,0 @@
-namespace Ryujinx.HLE.Gpu
-{
-    enum NvGpuEngineDmaReg
-    {
-        SrcAddress = 0x100,
-        DstAddress = 0x102,
-        SrcPitch   = 0x104,
-        DstPitch   = 0x105,
-        DstBlkDim  = 0x1c3,
-        DstSizeX   = 0x1c4,
-        DstSizeY   = 0x1c5,
-        DstSizeZ   = 0x1c6,
-        DstPosZ    = 0x1c7,
-        DstPosXY   = 0x1c8,
-        SrcBlkDim  = 0x1ca,
-        SrcSizeX   = 0x1cb,
-        SrcSizeY   = 0x1cc,
-        SrcSizeZ   = 0x1cd,
-        SrcPosZ    = 0x1ce,
-        SrcPosXY   = 0x1cf
-    }
-}