Port `examples`, `interactions`, etc., to use the new `examples`
form of `scribble/examples`. The main intended effect is to ensure
that errors are produced by examples only as specifically
indicated.
If a file or directory delete fails, try adjusting the file or directory
permissions to allow writes, then try deleting again. This process should
provide a more Unix-like experience and make programs behave more
consistently.
A new `current-force-delete-permissions` parameter provides access to
the raw native behavior.
