"non-batch" mode doesn't work for _delete_obj()

[Mike Bayer]

I never thought I'd find a use for batch=False but since now I have (nested sets), we need it for the delete phase also. We might consider reorganizing _save_obj() and _delete_obj() to be simpler and more efficient with the "non batch" mode, now that its widely established that executemany() behavior is not possible in any of these cases.

[Mike Bayer]

we don't actually need this for nested sets (and I still hate batch mode). The batch mode use case on save is that you can set the lft/rgt attribute of each row on INSERT, instaed of issuing a second UPDATE later. for a delete, this doesn't matter.

[Mike Bayer]

Removing milestone: 0.5.xx (automated comment)