Move some stuff around, apparently order maters.
Changed BOINC_OPTIONS_WXWIDGETS to find correct GTK toolset
update_forum_activities: handle team forum posts properly
web: in prefs form, say "0 means no limit" where appropriate

Also refactor some string translations
web: tweak
MGR: Update my fix for wxListCtrl / CBOINCListCtrl flicker on Mac (commit f8966bf) to match the fix made to wxWidgets trunk by wxWidgets personnel, as described in <http://trac.wxwidgets.org/ticket/16334#comment:2>.
MGR: Fix more deficiencies in Computing Preferences dialog reported by Juha.