XFE Prime Directive: Get SmartMail working

What's new:

• URL bar is back in business (ramiro)
• Navigation buttons work now (ramiro)
• Selector bar works (#ifdef MOZ_SELECTOR_BAR) (radha)
• Tree view column sorting, resizing (slamm)
• Toolbar context menus done (slamm)
• SMART_MAIL=1 is default now (mcafee)

• Cool projects: Cool projects and who's doing them
• netscape.public.mozilla.unix
• netscape.public.mozilla.unix.checkins
• How to pull the source and build it

• Bugzilla queries
• New Layout/XPFE effort
• netscape.public.mozilla.layout
• netscape.public.mozilla.xpfe