alongside the 'del' button is now presented a 'rename' button, which takes
the user to a new page, the 't=rename-form' page, which asks ther user for
the new name of the child and ultimately submits a POST request to the dir
for 't=rename' to perform the actual rename i.e. an attach followed by a
delete of children.
Also include the encoder portion of Bob Ippolito's simplejson-1.7.1 as
allmydata.util.json_encoder . simplejson is distributed under a more liberal
license than Tahoe (looks to be modified BSD), so redistributing it should be ok.