libical: revert r1130 (VTIMEZONE transitions)

[Allen Winter]

Howdy,

I intend to revert the old commit 1130 from 3 years ago for the upcoming 2.0 release.
Commit message:
"Fix TZ rules, make the VTIMEZONE specifier an exact mirror of the transitions in the
zone files, so it now uses absolute dates rather than trying to calculate a RRULE.
Patch frmo jejb, THanks!
Fixes bug IDs: 3432224, 3405041, 2096602
also the timezone test program passes 100% now."

It caused several problems pointed out by Patrick, see https://sourceforge.net/p/freeassociation/bugs/95/
reverting might bring back  https://sourceforge.net/p/freeassociation/bugs/34/ but that bug was from Patrick too

If anyone objects to this plan please let me know asap.

-Allen