Revert "Getting content is real heavy, cache it"

This reverts commit 77590ce659edca4538e671f1618d9bf3a9c7a9db.
Sanitize caching around get_children()
Thanks Batiste for the creds!
Invalidate parent, when dragging page items in the tree
Page must be invalidated on status change
Instead of queryset cache, do it clearer in model
Merge branch 'further_caching'