1.9.0

Fixes #45 Content/Media/Members picker throw an error on init
Fixes #42 Make it possible to hide a UI-O-Matic model from the tree
Fixes #41 Dropdown prop editor doesn't seem to set correct state after save
Implements #39 (Add ui localization keys on installation)
Implements #38 (Give admins access to UI-O-Matic section on installation)
Adds Datetimeoffset support (not for sql ce)