[contactsd] Trigger contacts-sync profiles when changes are detected

This commit adds logic to allow triggering of contacts sync profiles
when changes signals are received.  In order to be triggered, a profile
must be a contacts profile, it must be enabled, it must have to-remote
or two-way directionality, and it must have the always-up-to-date
setting set to true.
Merge pull request #64 from chriadam/alwaysuptodate

[contactsd] Trigger contacts-sync profiles when changes are detected