Cannot select Task List

[Scott White]

Crash report immediately displays when task list is selected. Running ZIm 0.66 on Ubuntu 14.04 system is up to date as of 2017/05/01. See crash report below

This is zim 0.66
Platform: posix
Locale: en_CA UTF-8
FS encoding: UTF-8
Python: (2, 7, 6, 'final', 0)
Gtk: (2, 24, 23)
Pygtk: (2, 24, 0)
No bzr version-info found

======= Traceback =======
  File "/usr/lib/python2.7/dist-packages/zim/actions.py", line 149, in do_activate
    self.__get__(instance, instance.__class__)()
  File "/usr/lib/python2.7/dist-packages/zim/actions.py", line 132, in func
    self.func(instance, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/zim/plugins/tasklist/__init__.py", line 161, in show_task_list
    dialog = TaskListDialog.unique(self, self.window, tasksview, self.plugin.preferences)
  File "/usr/lib/python2.7/dist-packages/zim/gui/widgets.py", line 2958, in unique
    dialog = klass(*args, **opts)
  File "/usr/lib/python2.7/dist-packages/zim/plugins/tasklist/gui.py", line 124, in __init__
    sort_order=self.uistate['sort_order']
  File "/usr/lib/python2.7/dist-packages/zim/plugins/tasklist/gui.py", line 458, in __init__
    self.refresh()
  File "/usr/lib/python2.7/dist-packages/zim/plugins/tasklist/gui.py", line 468, in refresh
    self._append_tasks(None, None, {})
  File "/usr/lib/python2.7/dist-packages/zim/plugins/tasklist/gui.py", line 542, in _append_tasks
    td = datetime.date(int(y), int(m), int(d)) - today
ValueError: month must be in 1..12

 zim -D
INFO: This is zim 0.66
DEBUG: Python version is sys.version_info(major=2, minor=7, micro=6, releaselevel='final', serial=0)
DEBUG: Platform is posix
DEBUG: No bzr version-info found
DEBUG: Not running from a source dir
DEBUG: Set XDG_DATA_HOME to /home/scott/.local/share
DEBUG: Set XDG_DATA_DIRS to [<Dir: /usr/share/ubuntu>, <Dir: /usr/share/gnome>, <Dir: /usr/local/share>, <Dir: /usr/share>]
DEBUG: Set XDG_CONFIG_HOME to /home/scott/.config
DEBUG: Set XDG_CONFIG_DIRS to [<Dir: /etc/xdg/xdg-ubuntu>, <Dir: /usr/share/upstart/xdg>, <Dir: /etc/xdg>]
DEBUG: Set XDG_CACHE_HOME to /home/scott/.cache
DEBUG: Dispatched command (u'-D',)

[Jaap Karssenberg (jaap.karssenberg)]

Apparently an invalid date was entered in the index table. Committed patch to prevent that.