Log Message:
Updated khal to 0.9.6.

0.9.6
=====
released 2017-06-13

* FIX set PRODID to khal/icalendar
* FIX don't crash on updated vcards
* FIX checking for RRULEs we understand
* FIX after editing an event in ikhal, make sure both the calendar and the
  eventcolumn are focused on the new date
* FIX no more crashes if only one event which is an overwritten instance is
  present in an .ics file
* FIX .ics files containing only overwritten instances are not expanded anymore,
  even if they contain a RRULE or RDATE
* FIX valid UNTIL entry for recurring datetime events

* CHANGE the symbol used for indicating a recurring event now has a space in
  front of it, also the ascii version changed to `(R)`
* CHANGE birthdays on leap 29th of February are shown on 1st of March in
  non-leap years

* NEW import and printics will read from stdin if not filename(s) are provided.
* NEW new entry points recommended for packagers to use.
* NEW support keyword `yesterday` for querying and creating events