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.
the final flatzone for every Zone should end at "current" for every *_to time. This is inaccurate, but accuracy is only guaranteed up to ?MAX_YEAR (=2500 by default).
that working, I fleshed out the few methods required to get ezic:utc_to_localtime/2 working, thus localtime/1 working. I've only tested localtime/1 at this point.
additionally, mnesia appears to have its data corrupted every time I stop and start a node. I've got to read up on working with mnesia; it's not behaving as I would expect.
add_offset was calculating DST differences wrong. It assumed to lose an hour, DST would be {-1,0,0}, in fact, DST went from {1,0,0} to {0,0,0}. add_offset now uses their differences (hence requires both as arguments)
normalize/2 was added to be able to set an arbitrary flag on a plain (i.e. native erlang datetime tuple) date. This is complicated by the fact that atoms "minimum", "max", etc. are still valid and need to fall through the normalization unaltered (for now).
ezic_zone:next/3 was not filtering the Zones to only those after UTCFrom. This may have caused an endless loop, always returning the earliest zone regardless of the progress of time. I wont know; I caught it rather early.
