Adds package.json.  Untracks node_modules/.  Upgrades to UglifyJS2.

Squashed commit of the following:

commit 177cec6092d77fcd931890da674c9be8976214df
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Sun Jun 2 13:05:27 2013 -0700

    Bit of cleanup and README update.

commit 95c695d40c916fe5c65399a198dbc3a6bc8e07ad
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Sun Jun 2 12:55:57 2013 -0700

    Adds package.json and upgrades to UglifyJS.

commit e956cc6507e08ec2f67f8e76b2c32befe49a1e60
Author: Jeremy Kahn <jeremyckahn@gmail.com>
Date:   Sun Jun 2 12:20:00 2013 -0700

    Removes old node_modules directory.