backbone v1.3.3 to 1.4.0 in package.json

[adamwirth]

trafficstars

The package.json devDependency requirement for backbone is version "1.3.3". The latest version of backbone is now 1.4.0.

Backbone's changelog is here: https://backbonejs.org/#changelog. In more detail, see here: https://github.com/jashkenas/backbone/compare/1.3.3...1.4.0#diff-0d56d0d310de7ff18b3cef9c2f8f75dc. The single main file backbone.js appears to be the only changed file that could affect backbone.syphon, but I'm not sure. Their dependencies haven't changed.