Added check for 'sequence-item' in sort attribute.

silently ignoring them.

In particular, copy or moved object has new ID *before* it gets
added to the collection.

when seeking past the end of the "file".

Waaa.

length > 1.  Basically, the leading n-2 elements get added to the parents,
and the n-1th element is substituted for the object being traversed.
This is needed for making certain objects surrogates for others.
We use this to enter long-running transactions as we traverse objects.
It might be useful for creating "symbolic links".

Checked in a change (that I meant to check in before that fixes a bug
in the way '.' is handled.  Basically, '.' should be handled as
if it isn't really there.

handling to allow the protocol to be ommitted.

getting the wrong "results".

unauthorized errors.