"schedule for" submenu functionality broken in 0.2

Setting XDG vars to use default dataset.

(gtg:13607): ClutterX11-CRITICAL **: Display connection already exists. You can only call clutter_x11_set_display() before clutter_init()

(gtg:13607): ClutterX11-WARNING **: clutter_x11_disable_event_retrieval() can only be called before clutter_init()
Traceback (most recent call last):
  File "/home/luca/Projects/gtg/0.2/GTG/taskbrowser/browser.py", line 1591, in on_schedule_for_tomorrow
    self.update_start_date(widget, "tomorrow")
  File "/home/luca/Projects/gtg/0.2/GTG/taskbrowser/browser.py", line 1582, in update_start_date
    task.set_start_date(self.get_canonical_date(new_start_date))
  File "/home/luca/Projects/gtg/0.2/GTG/taskbrowser/browser.py", line 825, in get_canonical_date
    if date == no_date:
  File "/home/luca/Projects/gtg/0.2/GTG/tools/dates.py", line 31, in __cmp__
    return cmp(self.to_py_date(), other.to_py_date())
AttributeError: 'str' object has no attribute 'to_py_date'