3.3.4

• #154: Converting ANNIVERSARY to X-ANNIVERSARY and X-ABDATE and
  vice-versa when converting to/from vCard 4.
• #154: It's now possible to easily select all vCard properties belonging to
  a single group with $vcard->{'ITEM1.'} syntax. (@armin-hackmann)
• #156: Simpler way to check if a string is UTF-8. (@Hywan)
• Unittest improvements.
• #159: The recurrence iterator, freebusy generator and iCalendar DATE and
  DATE-TIME properties can now all accept a reference timezone when working
  floating times or all-day events.
• #159: Master events will no longer get a RECURRENCE-ID when expanding.
• #159: RECURRENCE-ID for all-day events will now be correct when expanding.
• #163: Added a getTimeZone() method to VTIMEZONE components.