Add support for pre and post HLSL qualifier validation

The change makes it possible to define a const variable after the marked
type. Example "float const"

Test/hlsl.function.frag

@@ -3,9 +3,14 @@ float4 fun0()
     return 1.0f;
 }
 
-uint fun2(float4 col)
+float4 fun2(float4 const col)
 {
-    return 7;
+    return (1, 2, 3, 4);
+}
+
+uint fun3(const float4 col)
+{
+	return 7;   
 }
 
 float4 fun4(uint id1, uniform uint id2)
@@ -15,7 +20,7 @@ float4 fun4(uint id1, uniform uint id2)
 
 float4 fun1(int index)
 {
-    uint entityId = fun2(fun0());
+    uint entityId = fun3(fun2(fun0()));
     return fun4(entityId, entityId);
 }