Benefits of batch support...

++ Several Actions can be grouped together under a single annotated
revision.

++ Consistent with the typical VCS workflow.

++ Presents a more concise API for developers.

#------------------------

Reasons to not support batches...

-- Each revision will be limited to one stack

-- Actions cannot properly validate state during construction.

-- Batches make everything more complicated


#------------------------

The only current use case for batches is to add or import multiple
targets in one shot.  But you could also do this within a single
action, by allowing the action to take a list of targets as
attributes.


