Invalidate the Quit item of the application menu when running modal.

git-svn-id: http://seriss.com/public/fltk/fltk/branches/branch-1.3@10455 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
Fl::delete_widget() now hides a widget/window if it is shown (visible_r()).

This is useful (necessary) because in old (pre 1.1.6) which  didn't have
Fl::delete_widget() users would have called 'delete window', which would
have hidden a window and destroyed it as well. Now the widget/window is
hidden immediately, whereas it is destroyed delayed, which comes much
closer to the previous behavior and is useful for better window close
detection in Mac OS X cmd-Q handling.


git-svn-id: http://seriss.com/public/fltk/fltk/branches/branch-1.3@10456 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
Improves the cmd-Q handler as discussed in FLTK.coredev "Safe widget deletion ».

git-svn-id: http://seriss.com/public/fltk/fltk/branches/branch-1.3@10457 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
Remove static members of the Fl_X class that became unused.

git-svn-id: http://seriss.com/public/fltk/fltk/branches/branch-1.3@10458 ea41ed52-d2ee-0310-a9c1-e6b18d33e121