news volunteers: add link to volunteer app as suggested by Mark
add wine description by Jeremy White
ical/xcal url fix (reported by Niels Laukens)
unify terminology: events (not sessions)
bugfix: mismatching event sizes
enable subtitles for all event overviews
subtitle bugfix
campusmap: food
schedule_helpers: revert 219563f and 64e3808

Unbreak the damage done by the well-meaning attempt at adding
subtitles to the schedule pages.  I'll fix it properly when I'm
done being angry.