Improvements of editor (copy rows, bulk processing, css)

- Add the option to copy one or more rows in editor including all the fields within it.
- Bulk processing of fields (like bulk changing of names and settings with search & replace)
- Option to add custom CSS (or classes) to rows or perhaps even individual fields.
- Copy translations. For example if you want to use slightly different forms for en-US and en-UK but your default editing language is French, you have to edit both English versions individually. It would be much more convenient to just be able to copy translation from one language to another (say en-US to en-UK).