Added many shader source files

This should include the latest version of every shader that was in the
2007 SDK. It also includes a smattering of debug shaders, both VR
distortion shaders, and other assorted shaders that will hopefully be
useful.

None of these new files are included in the game shader DLL project. If
you need to modify one of these shaders for use in your mod you will
need to rename it so that you don't collide with the version of that
shader that lives in stdshader_dx9.dll.

mp/src/materialsystem/stdshaders/debugmrttexture_vs20.fxc

@@ -0,0 +1,29 @@
+#include "common_vs_fxc.h"
+
+struct VS_INPUT
+{
+	float3 vPos							: POSITION;
+	float2 vBaseTexCoord				: TEXCOORD0;
+};
+
+struct VS_OUTPUT
+{
+    float4 projPos					: POSITION;	
+	float2 baseTexCoord				: TEXCOORD0;
+};
+
+VS_OUTPUT main( const VS_INPUT v )
+{
+	VS_OUTPUT o = ( VS_OUTPUT )0;
+
+	float4 projPos;
+	float3 worldPos;
+
+	projPos = mul( float4( v.vPos, 1 ), cModelViewProj );
+	o.projPos = projPos;
+
+	o.baseTexCoord = v.vBaseTexCoord;
+	return o;
+}
+
+