v0.6.0

• BUGFIX Recurrent events with a THISANDFUTURE parameter could affect other
  events. This could lead to events not being found by the normal lookup
  functionality when they should and being found when they shouldn't. As the
  second case should result in an error that nobody reported yet, I hope nobody
  got bitten by this.
• new dependency for running the tests: freezegun
• new dependency for setup from scm: setuptools_scm
• khal now needs to be installed for building the documentation
• ikhal's should now support ctrl-e, ctrl-a, ctrl-k and ctrl-u in editable text
  fields (Thomas Glanzmann)
• ikhal: space and backspace are new (additional) default keybindings for right
  and left (Pierre David)
• when editing descriptions you can now insert new lines (Thomas Glanzmann)
• khal should not choose an arbitrary default calendar anymore (Markus
  Unterwaditzer)
• the zsh completion file has been updated (Hugo Osvaldo Barrera)
• new command import lets users import .ics files (Christian Geier)
• khal should accept relative dates on the command line (today, tomorrow and
  weekday names) (Christian Geier)
• keybinding for saving an event from ikhal's event editor (default is meta + enter) (Christian Geier)