Firefox true

Addresses issue #1 

UglifyJS compresses `(function(){})()` as `!function(){}()` to save one character. This also causes the statement to return `true` instead of `undefined`, which firefox then outputs in the browser. The solution is to add append `undefined` to the uglified output.

Relevant SO: http://stackoverflow.com/questions/3755606/what-does-the-exclamation-mark-do-before-the-function