[SyncEvolution] Libical 1.0 bug fixed (was: Re: SyncEvolution release process)

* ical: workaround for libical 1.0 builtin timezone change libical 1.0 started to return VTIMEZONE definitions with multiple absolute transition times instead of RRULEs. This causes problems when exchanging data with peers (see https://sourceforge.net/p/freeassociation/bugs/95/). In SyncEvolution, this affected sending an event using New Zealand time in vCalendar 1.0 format to a phone, because the internal, out-dated definition of the time zone in libsynthesis was used as fallback when loading RRULE-based timezone definitions from libical failed (see "[SyncEvolution] Some events showing wrong time on phone"). It might also affect exchanging data with CalDAV peers (not tested). The workaround is to include the original code from libical.