Adds ajax actions for clipboard items

Adds ajax actions for clipboard items

If a clipboard item's parameters contain `className` and `actionName`, an AJAX proxy action is executed with those parameters and the marked object ids.

This spares us writing that as event listeners for the `clipboardAction` event.

Additional changes:

* Adds `removeArrayValue` function.
* Adds the list item parameters as a third parameter for the event listener on `clipboardAction`.