This release of SDML expands the scope of the "navigator", which was
introduced in release 3.3, so that it can be used to browse
simulation structures (objects, agents, assumptions etc.) as well as
modules.

A special kind of navigator, the "search navigator", is introduced.
It encapsulates the facilities of the old-style symbol search tool
and the "Find Object" pane in old-style object/agent browsers.

Navigators now replace all old-style browsers on module and
simulation structures. However, the tutorial has not yet been
rewritten for navigators, so the old-style browsers are still
retained and can be used by default (if the option in the "Browsers"
pane of the "settings tool" that can be opened from the "File" menu
of the launcher is set accordingly).