Wren Memory Leaks

[PolyVector]

A couple memory leaks regarding Wren:

wrensupport.d: updateAndReturnIfChanged() leaks a copy of lastSource whenever lastSource==newSource, which happens on repeat calls. wrensupport.d: callPluginMethod()->interpret()->wrenInterpret() appeared to be leaking, but I forgot to take notes on this. I believe this function was in the Wren library itself and not part of Dplug.