Add -topLevel option

Add -topLevel option

This persistent Boolean option determines if the auxiliary windows
(Game List, Move List, Engine Output, Eval Graph, Tags and Comment)
use top-level shells (with their own icon on the task bar, and
independently closable). Other dialogs will always use transient shells.
(Also he modal Error and Promotion dialogs, for which the modality
presumably only serves to pop them down without special attention.)
A control for this was added in the General Options dialog.