Add jQuery as an explicity dependency of lib/component.js

Hi there!

I've been trying to get Flight running in Node, and I'm bumping into a problem which I *think* might have a trivial solution. I've had some success getting Flight itself loaded via RequireJS, but when I try to load an actual component the following error stops me in my tracks:

    $ node experiment.js 
    
    /home/h2s/src/tdd-flight/components/flight/lib/component.js:175
              if ($.browser.msie) {
                  ^
    ReferenceError: $ is not defined

The problem here is that [flight/lib/component.js](https://github.com/twitter/flight/blob/master/lib/component.js) makes rather liberal use of the jQuery `$` global. Presumably this isn't a problem in the browser where you can simply load jQuery via `<script>` tags and then assume it's there. But in a Node environment it was getting in the way of using Flight at all.

I was able to work around this issue by making a very slight tweak to component.js so that it loads jQuery as an explicit dependency. This pull request contains that tweak. It seems likely that there is more to this issue than the few lines I've changed, but given my lack of familiarity with the codebase I decided the best thing was to send it anyway to at least start the conversation.