HLSL: add Buffer support for Load method

Test/hlsl.load.buffer.dx10.frag

@@ -0,0 +1,38 @@
+uniform Buffer <float4> g_tTexbf4_test : register(t0);
+
+Buffer          g_tTexbf4;  // default is float4
+Buffer <int4>   g_tTexbi4;
+Buffer <uint4>  g_tTexbu4;
+
+struct PS_OUTPUT
+{
+    float4 Color : SV_Target0;
+    float  Depth : SV_Depth;
+};
+
+uniform int   c1;
+uniform int2  c2;
+uniform int3  c3;
+uniform int4  c4;
+
+uniform int   o1;
+uniform int2  o2;
+uniform int3  o3;
+uniform int4  o4;
+
+PS_OUTPUT main()
+{
+   PS_OUTPUT psout;
+
+   // Buffer
+   float4 r00 = g_tTexbf4.Load(c1);
+   int4   r01 = g_tTexbi4.Load(c1);
+   uint4  r02 = g_tTexbu4.Load(c1);
+
+   // TODO: other types that can be put in sampler buffers, like float2x2, and float3.
+
+   psout.Color = 1.0;
+   psout.Depth = 1.0;
+
+   return psout;
+}