Easy Testing and Code Coverage Metrics. 

I saw that one of your goals in the road map was better test coverage. I was curious to see what level of coverage you already had, so I added karma to the project to make testing easier. It also allows you to checkout your coverage metrics and see which lines are not covered in your current test suite. 

Your initial metrics are pretty good. 

Statements: 86.49% (224 / 259)      
Branches: 80.45% (107 / 133)      
Functions: 79.31% (23 / 29)      
Lines: 86.49% (224 / 259)

If you accept this pull request it is easy to add support for travis ci and have ci run your tests for each PR you get in the future.