Jasmine specs for navbar affix

* travis will now run `rake jasmine:ci`, hopefully without suffering the conflicts experienced in LocalSupport
* `jasmine-jquery.js` no longer copy-pasted into `spec/javascripts/helpers`, instead it's pulled in from asset pipeline by an additional line in `jasmine.yml`
* navbar affix functionality is now unit tested
* for testing purposes, `application.js` functionality is now exposed via `$.fn.BryanHATESTHIS`, instead of hiding in an anonymous function
* bug fixed where reloading the page while scrolled down doesn't automatically affix the navbar