Set up tests

[suluke]

Due to the nature of this project, testing is a difficult task. I am also opposed to making headless browser environments (e.g. phantom) a requirement for this project. Here are some ideas, though, how we can automate some tests:

1. Check that the plugin does not cause errors when loaded
2. Validate html structure of the widget in different contexts, e.g. after initialization, after loading a specific plugin... This can be done using only lightweight DOM-simulation libraries like cheerio.
3. Validate events are triggered on certain actions, e.g. change on clearSelection()

More ideas will be documented here when available