Added page-editor support for droplinks
Added page-editor support for date-times
Added page-editor support for droptrees
Added support for custom display fields in droplists and droptrees
Added referenced item mapping, fix for view mode
Fixed date-time field crashes
Fixed image rendering after change in the edit mode
Small fixes of date-time and link renderings in the edit mode
Added support for empty selections in droplinks/droptrees
Updated to v0.4