Add comment header to config file, and cleanup
setup.py: Add glade backup to cleanup list
Eliminate IMAP XLIST from gnome-gmail

It is deprecated, per

  https://developers.google.com/gmail/imap_extensions#xlist_is_deprecated

to be replaced with RFC6154 extended list attributes.
Store oauth tokens in keyring

Check the stored access and refresh token before querying the user for auth.
gnome-gmail: clean up imports
gnome-gmail: Upgrade notifications

I was using dbus. User gi.repository.Notify instead.