Define Stylus Language

On the [Try Stylus Online](http://learnboost.github.com/stylus/try.html) page, it utilizes CodeMirror and a [custom mode](http://learnboost.github.com/stylus/css-mode.js). I borrowed the code from here with some minor modifications (whitespace, curly braces, ===, etc) and this is what i've been using for weeks now.

The only thing I can't figure out is, if I replace any of the 4 occurrences of a ```!=``` with ```!==``` and try to open a stylus file, brackets hangs... 3 of these occurrences are in while loops, iterating over the characters, and even in the core CodeMirror modes such as [javascript](https://github.com/marijnh/CodeMirror/blob/master/mode/javascript/javascript.js#L65) only ```!=``` is used.