Delayed updates :) review please?

[Craig de Stigter]

Hi list

I spent the last two work days implementing delayed updates for django-mptt.

I've got a pull request here: https://github.com/django-mptt/django-mptt/pull/201

I'd like to be merging it by Monday, so if anyone could take a look at the code, maybe test it out, and add any comments to the pull request, I'd appreciate it :)

Thanks

Craig de Stigter