Merge pull request #9 from Kampfgnom/geenen

Geenen
Improved events and contact infos.
wip
wip
Fix client page. Improve note-sync.
Added a "deleted flag" for objects, which is also respected by sortfiltermodel.
Improved locking even further.
Added the timeout parameter to Qp::synchronize, which specifies a timespan in which no updates should be fetched.
Improved database sync, sorting and filtering.
Improved handling of deleted objects and some other general improvements