Starting a batch call batch::operation(name, item). In the case of
adding photos name = add and item is the parent of the new items.
When the operation is finished the batch::end_operation(name) is
called.
operation and end_operation events are called. Handlers
(i.e. item_created) can call batch::in_progress(name) to determine if
a batch is being processed.
start_batch and end_batch add and remove the batch id from the
session. Modules wishing to do batch processing, just need to fire
the start_batch and end_batch events. Other modules that need to be
aware of batches (i.e. notifications) just check the session for "batch_id".
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
1) Upload requests are serialized so we don't over load the server or get
race conditions occurring.
2) new albums are created based on the file structure of the
authorized path that is the source directory.
