Depend on `css-mediaquery` to match media query expressions more robustly

## Background

Hey! Love the work that you've done with this grunt task. @ericf and I have been working on a [Media Query Parser and Matcher](https://github.com/ericf/css-mediaquery) that is more robust in parsing and matching media queries. We updated your grunt task to depend on this module under-the-hood. 

## What's in this PR

* Stripped out the parsing/matching logic inside `tasks/lib/stripmq.js` to depend on **css-mediaquery** instead. This module follows the W3C Recommendations for [CSS3 Media Queries](http://www.w3.org/TR/css3-mediaqueries/) and [CSS3 Values and Units](http://www.w3.org/TR/css3-values/). It supports all of the [Media Features](http://www.w3.org/TR/css3-mediaqueries/#media1) and will properly convert values to a common unit before comparing them.
* Added a greater number of sane defaults.
* Updated the test files, so that you can still test this out by typing `grunt`.
* Added a `test/run.js`. This is useful to run if you want to debug what's happening with `node-inspector`.
* Minor changes to `Gruntfile.js`, `package.json`, and `.gitignore`.

Hope you like it! LMK what you think.