Add cloneInto function that will: use Cu.cloneInto when available, or, if not available, create __exposedPropes__ if it's an object.

In this case we don't want just forward the e.detail. I think we shall re-create the object, e.g. `var detail = Cu.cloneInto({query: e.detail.query, caseSensitive: e.detail.caseSensitive, ...}, contentWindow);`