Issue #7: Some Zones no longer observing DST are broen.
The matchspec generation function for universal time was wrong,
whereas it was fine for wall and local times. Fixing that line, and
considering the `current` flatzone time, was enough to get TZs like
Tokyo and Jamaica working correctly in tested cases.
Like in d98eed, errors are now returned as values rather than crashing
processes. This is a short-term solution for consistency, and can be
refactored to a saner model later.