Unflops the spur in +en-beam, +de-beam, and everything that calls either
of those, or works with the consequences of their output.
This includes clay's interface for mounting and unmounting, which now
no longer expects the arguments to contain an old-style spur.
No longer abuse the desk field, instead making use of the path. Reject
any scries outside of the local ship, empty desk and current time as
invalid.
Expose ducts only under a debug endpoint, nothing else should care about
being able to inspect them.
Add scry endpoints for the very next timer (if any), and all timers up
to and including a specified timestamp.
