Here is an update! There is now a more powerful command that administrators may use to clear up an area that's littered with various creatures. No more killing mobs on lots by accident, as this command ignores lots by default. Also, it allows a range, so administrators could remove a pool of squid on your lot, and ignore everything else around it. The biggest advantage of it is to allow for targeting of mob groups. Cow -> animals -> creatures -> entity (which selects all entities). This also clears vehicles, like minecarts, and the like.
There is more news We don't plan to sleep on the job, as we are going to work on IDP until it is ready for release. It shouldn't be too long now, so just sit patient. We have a big list of changes, that I'm sure you all will enjoy very much.
The IDP Development Team