Remove some redundancy from the DValue hierarchy: all subclasses had a 'type' field and identical implementations of virtual function getType(). Move these to DValue itself, and make getType() non-virtual.

// idouble

module typeinfo1.ti_idouble;

private import typeinfo1.ti_double;

class TypeInfo_p : TypeInfo_d
{
    char[] toString() { return "idouble"; }
}