events: start_add_batch and end_add_batch. The parameter is a batch
id which is generated on the first add request. The protocol is call
the add_photo as many times as required and then call finish when
done.
Also renamed the add method in local_import to add_photo so it is
consistent with simple_uploader
This requires a little trickery to proxy the session id and user agent
through the ActionScript code so that we can assume the same session
in the uploader. It's also using its own path to add photos since
we'll want to have a slightly different protocol for dealing with
responses (as opposed to JSON or HTML).
A work in progress for sure, but it's already better than what we had before.?\024