Miscellaneous tidyings:
* Change the timeout to something more appropriate for real use.
* Check assumptions about object types when binding the socket. In
particular, don't zap the socket if it's really something else.
* In @p_request@, return a failure if the shell command returned
nonzero. Fix a bug in @p_get@ which incorrectly passes on a success
code when this happens.
* Dispose of the locked memory in client mode to avoid being
antisocial.
* Also in client mode, don't report closure from the server if we're
running noninteractively.
* Insert a missing option letter into the usage string.
* Change to the root directory after forking in daemon mode.