Changes

Need a fully app-independent toolkit. At the moment there are still a lot of places with #ifdef MOZ_PHOENIX or #if MOZ_THUNDERBIRD, which really [https://bugzilla.mozilla.org/show_bug.cgi?id=270235 hinders] app development for other toolkit apps. There are also some files (see bug [https://bugzilla.mozilla.org/show_bug.cgi?id=250868 250868], bug [https://bugzilla.mozilla.org/show_bug.cgi?id=250793 250793] and bug [https://bugzilla.mozilla.org/show_bug.cgi?id=250867 250867]), which are essentially the same for all toolkit apps, but have to be carried in every app-package, making bug-fixing and maintenance a real nightmare.