KolabMailSynchronizer: improved modtime comparisons for EDS data
KolabMailSynchronizer: improved modtime comparisons for EDS data

* better handling of NULL modtimes in kolab_mail_synchronizer_act_on_econtact()
  and kolab_mail_synchronizer_act_on_ecalcomp()
* TODO: libical chokes on some modification time formats

GNOME/evolution-kolab,GNOME/evolution-kolab