Table-driven construction of Prefs dialog. A factory for each kind of panel...

... and maybe a future plug-in protocol to break compilation dependency on
all of the PrefsPanel subclasses.

src/prefs/ProjectsPrefs.cpp

@@ -79,3 +79,8 @@ bool ProjectsPrefs::Apply()
 
    return true;
 }
+
+PrefsPanel *ProjectsPrefsFactory::Create(wxWindow *parent)
+{
+   return new ProjectsPrefs(parent);
+}