includeFuncEntry: Added support for function arguments compatible with the '-func' post-processing option

e.g.

functions
{
    #includeFunc mag(U)
}

executes 'mag' on the field 'U' writing the field 'mag(U)'.

The equivalent post-processing command is

postProcess -func 'mag(U)'

tutorials/compressible/sonicFoam/laminar/shockTube/system/controlDict

@@ -47,8 +47,7 @@ runTimeModifiable true;
 
 functions
 {
-    #includeFunc mag
-    mag{field U;}
+    #includeFunc mag(U)
 }
 
 // ************************************************************************* //