* Instead of calling 'zpool destroy' manually, use the function destroy_pool()
  + Modify this to accept (optional) options as first param to function.
  + Duplicate this behaviour with 'zfs destroy' with new function destroy_dataset()
  + Duplicate functionality in destroy_snapshot() and destroy_clone()
    > basically the same as the new destroy_dataset()
  = Both of these functions verifies that the pool/dataset already exist, so no
    need to do the verification first, before calling the function(s).
    This (will) give us more control over what is destroyed and not...
* Make sure that all 'ZFS {mount|unmount} -a' only operates on a testpool.