Crash if Google login doesn't work

[Adam J. Lincoln]

If Google's servers don't respond right, pygpal crashes with:

Traceback (most recent call last):
  File "./pygpal.py", line 341, in ?
    pygpal = Pygpal()
  File "./pygpal.py", line 61, in __init__
    curses.wrapper(self.interactive_main_loop)
  File "/usr/lib/python2.4/curses/wrapper.py", line 44, in wrapper
    return func(stdscr, *args, **kwds)
  File "./pygpal.py", line 130, in interactive_main_loop
    calendar_timezones = self.eventpool.login()
  File "/home/adam/Desktop/DoNotBackup/sourceCode/bzrbranches/pygpal/trunk/Eventpool.py", line 34, in login
    return self.remotewrapper.login()
  File "/home/adam/Desktop/DoNotBackup/sourceCode/bzrbranches/pygpal/trunk/Remotewrapper.py", line 38, in login
    feed = self.service.GetOwnCalendarsFeed()
  File "/usr/local/lib/python2.4/site-packages/gdata/calendar/service.py", line 85, in GetOwnCalendarsFeed
    return self.Get(uri, converter=gdata.calendar.CalendarListFeedFromString)
  File "/usr/local/lib/python2.4/site-packages/gdata/service.py", line 1008, in Get
    encoding=encoding, converter=converter)
  File "/usr/local/lib/python2.4/site-packages/gdata/service.py", line 1018, in Get
    raise RequestError, {'status': server_response.status,
gdata.service.RequestError: {'status': 500, 'body': 'Service Error: Could not generate feed.', 'reason': 'Internal Server Error'}

This is probably best solved by creating a "local-only" or offline mode separately, then catching this exception and forcing offline mode when it's seen.