update backbone to 1.1.1 and underscore to 1.6.0

[Backbone 1.1.1](http://htmlpreview.github.io/?https://raw.github.com/jashkenas/backbone/1.1.1/index.html)
[Underscore 1.6.0](http://htmlpreview.github.io/?https://raw.github.com/jashkenas/underscore/1.6.0/index.html)