VideoCommon: keep a copy of the const buffer in VideoCommon

The upload in the backend isn't done, it's just pushed by the mostly removed SetMulti*SConstant4fv.
Also no optimizations was done on VideoCommon side, but I can start now :-)

Sorry for the hacky way, but I think this is a nice (working) snapshot for a much bigger change.

Source/Core/VideoCommon/Src/ConstantManager.h

@@ -0,0 +1,46 @@
+// Copyright 2013 Dolphin Emulator Project
+// Licensed under GPLv2
+// Refer to the license.txt file included.
+
+#ifndef _CONSTANTMANAGER_H
+#define _CONSTANTMANAGER_H
+
+// all constant buffer attributes must be 16 bytes aligned, so this are the only allowed components:
+typedef float float4[4];
+typedef u8 uchar16[16];
+typedef s8 schar16[16];
+typedef u16 ushort8[8];
+typedef s16 sshort8[8];
+typedef u32 uint4[4];
+typedef s32 sint4[4];
+
+struct PixelShaderConstants
+{
+	float4 colors[4];
+	float4 kcolors[4];
+	float4 alpha;
+	float4 texdims[8];
+	float4 zbias[2];
+	float4 indtexscale[2];
+	float4 indtexmts[6];
+	float4 fog[3];
+
+	// For pixel lighting
+	float4 plights[40];
+	float4 pmaterials[4];
+};
+
+struct VertexShaderConstants
+{
+	float4 posnormalmatrix[6];
+	float4 projection[4];
+	float4 materials[4];
+	float4 lights[40];
+	float4 texmatrices[24];
+	float4 transformmatrices[64];
+	float4 normalmatrices[32];
+	float4 posttransformmatrices[64];
+	float4 depthparams;
+};
+
+#endif