Fix jstree drag drop bug (upgrade to v3.0.6)

Notable change: error indicators in the tree are now easier to spot, and the tooltip (not new) will direct you to the source of the problem.
![screen shot 2014-10-31 at 9 34 54 am](https://cloud.githubusercontent.com/assets/464726/4862137/b0b708da-6109-11e4-9eca-9d6717203502.png)