Code review comment for lp:~leonardr/lazr.restful/operation-removed-in

This branch introduces the @operation_removed_in_version method, which stops an operation from having any configuration for the given version number. This has two uses: 1. to remove a named operation as of a current version. 2. to reset the named operation's configuration so that you can do something strange to it like change a read operation to a write operation. My test gives examples of both.

Most of the changes to the doctest are caused by my moving the test elsewhere in the document.