Checkbox list should support preview mode
Fixes #373 - FormController can now accept different form fields for create,update,preview
Add new options to RelationController (view mode): recordUrl, recordOnClick, toolbarButtons
Clicking a record in readOnly mode will open the manage form in preview mode
Use "recordOnClick: null" to retain the original behavior
Clean key & Update Ru lang
Correcting class name for missing relation exception
Merge pull request #827 from chrisnharvey/patch-1

Correcting class name for missing relation exception