Require a ProjectWindow as ancestor of effect dialog...

... by passing parent as reference, not pointer, and testing in the dialog
factory function.

This is important so that we know the lifetime of an effect dialog, even when
it is non-modal, is bounded by the lifetime of the associated project.

src/BatchProcessDialog.cpp

@@ -1104,7 +1104,7 @@ void MacrosWindow::OnEditCommandParams(wxCommandEvent & WXUNUSED(event))
    auto command = mMacroCommands.GetCommand(item);
    wxString params  = mMacroCommands.GetParams(item);
 
-   params = MacroCommands::PromptForParamsFor(command, params, this).Trim();
+   params = MacroCommands::PromptForParamsFor(command, params, *this).Trim();
    Raise();
 
    mMacroCommands.DeleteFromMacro(item);