Include full license text in non-AGPLed JavaScript

CiviCRM distributes JavaScript under a variety of free software licenses. Except for one file under the WTFPL (jquery-fieldselection.js), all of these licenses require that a copy of the license terms accompany the software. Unfortunately, when this JavaScript is served from a running CiviCRM install, a copy of the license isn't always included.

We addressed this issue on our own installation by manually adding a copy of the appropriate license to each JavaScript file, in a multi-line comment near the top of the file. I'm not sure if there are smarter ways to do this, but one way or another, a full copy of the license text should accompany the JavaScript whenever it's served to a user (except in cases where the JavaScript is specific to CiviCRM, and you can grant an additional permission to waive the condition – see #8803).