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/WaterRefractFresnel_ps11.psh

@@ -0,0 +1,24 @@
+ps.1.1
+
+; t0: 
+;		texture: dudv map
+;		texcoords: dudvmap texcoords
+; t1:
+;		texture: refraction render target
+;		texcoords: 
+
+tex t0			; sample dudv map
+texbem t1, t0		; refraction
+tex t2			; The normal map
+tex t3			; Normalize the tangent-space vector to the eye
+
+; dot eye-vector with per-pixel normal from t2
+dp3_sat r1.rgba, t2_bx2, t3_bx2
+
+mul r0.a, 1-r1.a, 1-r1.a			; squared
+mul r0.a, r0.a, r0.a				; quartic
+
+mul r0.rgb, t1, c0
++mul_sat r0.a, r0.a, 1-r1.a			; quintic
+
+add_sat r0.a, r0.a, v0.a			; cheap water distance