Remove underscore dependency

* Replace _.keys with Object.keys
* Include link to compatibility table
Create a jasmine test suite for front end

* Add jasmine js to lib
* Create a _spec directory in /js
* Create a basic SpecRunner that includes all the app's current
dependencies, crudely
Correctly display the track duration. Fixes #3

* Create a MainController spec and add to SpecRunner
* Update durationInText method to pad seconds with zeros
* Write test cases