Ref property values now appear in the select lists.
Finished the placeholder implementation and applied to the neccessary widgets (not all of them support this attribute).
Added more robust support for required fields (* notification on fields, and boolean and radios widgets now support the required attribute).
Created a fitler property, which is used to filter record sets on ref fields.
Added the ability to provide a filter, sort and select values for ref fields.
Implemented the ability to save models with non-required ref fields.
Fixed issue with pre.save not passing on req object.