Updated py-icalendar to 3.10.

3.10 (2016-05-26)
-----------------

New:

- Updated components description to better comply with RFC 5545.
  Refs #183.
  [stlaz]

- Added PERIOD value type to date types.
  Also fixes incompatibilities described in #184.
  Refs #189.
  [stlaz]

Fixes:

- Fix testsuite for use with ``dateutil>=2.5``.
  Refs #195.
  [untitaker]

- Reintroduce cal.Component.is_broken that was removed with 3.9.2.
  Refs #185.
  [geier]

3.9.2 (2016-02-05)
------------------

New:

- Defined ``test_suite`` in setup.py.
  Now tests can be run via ``python setup.py test``.
  [geier]

Fixes:

- Fixed cal.Component.from_ical() representing an unknown component as one of the known.
  [stlaz]

- Fixed possible IndexError exception during parsing of an ical string.
  [stlaz]

- When doing a boolean test on ``icalendar.cal.Component``, always return ``True``.
  Before it was returning ``False`` due to CaselessDict, if it didn't contain any items.
  [stlaz]

- Fixed date-time being recognized as date or time during parsing.
  Added better error handling to parsing from ical strings.
  [stlaz]

- Added __version__ attribute to init.py.
  [TomTry]

- Documentation fixes.
  [TomTry]

- Pep 8, UTF 8 headers, dict/list calls to literals.
  [thet]

3.9.1 (2015-09-08)
------------------

- Fix ``vPeriod.__repr__``.
  [spacekpe]

- Improve foldline() performance. This improves the foldline performance,
  especially for large strings like base64-encoded inline attachements. In some
  cases (1MB string) from 7 Minutes to less than 20ms for ASCII data and 500ms
  for non-ASCII data. Ref: #163.
  [emfree]

3.9.0 (2015-03-24)
------------------

- Creating timezone objects from VTIMEZONE components.
  [geier]

- Make ``python-dateutil`` a dependency.
  [geier]

- Made RRULE tolerant of trailing semicolons.
  [sleeper]

- Documentation fixes.
  [t-8ch, thet]

3.8.4 (2014-11-01)
------------------

- Add missing BYWEEKNO to recurrence rules.
  [russkel]

(wiz)