This reverts commit 4871d896.

Directly provide the instance document in the request.

Packing can be fetch from instance directly.

Created instance can be now accessed directly from request.

New logic creates hosting deliveries really fast.

New logic disallows coexistence of slave and software instance with same title.

Also rename expected exception.

Use correct method to request destruction.
Use slap tool to inform about destruction.

It is hard to remove elements from sequence, and get will return value of
available key, but resetting sets to '', so fallback again to started state.