New app: contacts

apps/contacts/appinfo/app.php

apps/contacts/appinfo/info.xml

apps/contacts/carddav.php

apps/contacts/css/styles.css

apps/contacts/details.php

apps/contacts/img/icon.png

apps/contacts/index.php

apps/contacts/js/interface.js

apps/contacts/lib/addressbook.php

apps/contacts/lib/connector_sabre.php

apps/contacts/photo.php

apps/contacts/templates/_contacts.php

apps/contacts/templates/_details.php

apps/contacts/templates/index.php