HLSL: Switch to generic selector, but using GLSL #version 400 rules.

Next step is to modify for HLSL rules.

Test/hlsl.overload.frag

@@ -0,0 +1,35 @@
+// function selection under type conversion
+void foo1(double a, uint b)  {}
+void foo1(double a, int b)   {}
+void foo1(double a, float b) {}
+void foo1(double a, double b){}
+
+float4 PixelShaderFunction(float4 input) : COLOR0
+{
+    double d;
+    uint u;
+    int i;
+    float f;
+
+    foo1(d, d);
+    foo1(d, u);
+    foo1(d, i);
+    foo1(d, f);
+
+    foo1(f, d);
+    foo1(f, u);
+    foo1(f, i);
+    foo1(f, f);
+
+    foo1(u, d);
+    foo1(u, u);
+    foo1(u, i);
+    foo1(u, f);
+
+    foo1(i, d);
+    foo1(i, u);
+    foo1(i, i);
+    foo1(i, f);
+
+    return input;
+}