Move GPU emulation from Ryujinx.HLE to Ryujinx.Graphics and misc changes (#402)

* Move GPU LLE emulation from HLE to Graphics

* Graphics: Move Gal/Texture to Texture

* Remove Engines/ directory and namespace

* Use tables for image formats

* Abstract OpCode decoding

* Simplify image table

* Do not leak Read* symbols in TextureReader

* Fixups

* Rename IGalFrameBuffer -> IGalRenderTarget

* Remove MaxBpp hardcoded value

* Change yet again texture data and add G8R8 flipping

* Rename GalFrameBufferFormat to GalSurfaceFormat

* Unident EnsureSetup in ImageHandler

* Add IsCompressed

* Address some feedback

Ryujinx.Graphics/Texture/TextureSwizzle.cs

@@ -0,0 +1,11 @@
+namespace Ryujinx.Graphics.Texture
+{
+    public enum TextureSwizzle
+    {
+        _1dBuffer           = 0,
+        PitchColorKey       = 1,
+        Pitch               = 2,
+        BlockLinear         = 3,
+        BlockLinearColorKey = 4
+    }
+}