Fix test case
Remove SumatraPlugin.perform() placeholder

Defining this method in the interface was screwing up inheritance,
so we're just instructing users to define this method. The fat
arrow is the culprit here, and I'm not sure how to fix that now
that CoffeeScript 1.6 introduced those extension changes..
Improve the syntax of the runtime helper function
Build/test the first working version of Sumatra!