Rendertarget attachments, texture and image changes (#358)

* Add multiple color outputs for fragment shaders

* Add registers and gal enums

* Use textures for framebuffers and split color and zeta framebuffers

* Abstract texture and framebuffer targets as an image

* Share images between framebuffers and textures

* Unstub formats

* Add some formats

* Disable multiple attachments

* Cache framebuffer attachments

* Handle format types

* Add some rendertarget formats

* Code cleanup

* Fixup half float types

* Address feedback

* Disable multiple attachments in shaders

* Add A4B4G4R4 image format

* Add reversed section for image enums

Ryujinx.Graphics/Gal/OpenGL/OGLRenderer.cs

@@ -23,7 +23,9 @@ namespace Ryujinx.Graphics.Gal.OpenGL
         {
             Buffer = new OGLConstBuffer();
 
-            FrameBuffer = new OGLFrameBuffer();
+            Texture = new OGLTexture();
+
+            FrameBuffer = new OGLFrameBuffer(Texture as OGLTexture);
 
             Rasterizer = new OGLRasterizer();
 
@@ -31,8 +33,6 @@ namespace Ryujinx.Graphics.Gal.OpenGL
 
             Pipeline = new OGLPipeline(Buffer as OGLConstBuffer, Rasterizer as OGLRasterizer, Shader as OGLShader);
 
-            Texture = new OGLTexture();
-
             ActionsQueue = new ConcurrentQueue<Action>();
         }