HLSL: Add scoping operator, accept static member functions, and support calling them.

Test/hlsl.staticMemberFunction.frag

@@ -0,0 +1,22 @@
+struct Test
+{
+    float4 memVar;
+    static float4 staticMemFun(float4 a) : SV_Position
+    {
+        return 2 * a;
+    }
+    static int staticMemFun(int a) : SV_Position
+    {
+        return 2 + a;
+    }
+    int i;
+};
+
+float4 main() : SV_Target0
+{
+   Test test;
+   float4 f4 = float4(1.0,1.0,1.0,1.0);
+   f4 += Test::staticMemFun(float4(5.0f,5.0f,5.0f,5.0f));
+   f4 += Test::staticMemFun(7);
+   return f4;
+}