Code cleanup wings_menu

Split wings_menu to two modules one handling
toplevel menu and popups, i.e. wx menus.

The wings_wm_menu handles the windows menus for autouv
and other windows using the old opengl style.
Fix loading prefs
Tweak menus
Fixes some submenus (autouv)
Remove menubar from (other) geometry windows
Remove the the obsolete jpeg plug-in
Fix the 'make macosx' and 'make unix' targets

Packaging a release is messy with different shell scripts for different
platforms. Unify the packaging script into an escript called tools/release.

The 'makeself' script needed to pack the Unix release is quite small, so
we can as well put a copy of it in the 'unix' sub-directory so that we
don't need to download and install it ourselves.
Mac: Teach Wings to open a .wings file that was clicked