Change location parentage UI

http://manage.dimagi.com/default.asp?139600
I also made some other UI improvements as per @biyeun 's suggestions
![location parentage](https://cloud.githubusercontent.com/assets/2367539/4621468/b8238620-532b-11e4-965f-67326ee1f04b.png)
This nested form look is suboptimal, but fixing it requires changes to a whole bunch of stuff so I gave up.