Add support for Vertex Program A and other small shader improvements (#192)

* Add WIP support for Vertex Program A, add the FADD_I32 shader instruction, small fix on FFMA_I encoding, nits

* Add separate subroutines for program A/B, and copy attributes to a temp

* Move finalization code to main

* Add new line after flip uniform on the shader

* Handle possible case where VPB uses an output attribute written by VPA but not available on the vbo

* Address PR feedback

Ryujinx.Graphics/Gal/IGalShader.cs

@@ -6,6 +6,8 @@ namespace Ryujinx.Graphics.Gal
     {
         void Create(IGalMemory Memory, long Key, GalShaderType Type);
 
+        void Create(IGalMemory Memory, long VpAPos, long Key, GalShaderType Type);
+
         IEnumerable<ShaderDeclInfo> GetTextureUsage(long Key);
 
         void SetConstBuffer(long Key, int Cbuf, byte[] Data);