Improved "environment" functionality - Tracking and control of loaded js/css libraries.

[jwildfire]

Update: Keeping track of env objects was going to be a pain, so refactored to take a much simpler approach

Revised approach

CAT will display links to all loaded <link> and <script> tags under the environment section of the CAT controls. Link tags will have a toggle that allows the user to enable/disable links to see how css effects the charts. Users can add any css files they want to the page hosting the CAT instance to facilitate testing of different environments.

Not going to deal with "unloading" scripts at this time.

Original plan

Add support for new config.env option where config.env is an array with objects that have the following properties:

config.env.label - a human readable name for the environment
config.env.js - an array of paths for javascript to be loaded before rendering the chart
config.css.js - an array of paths for css to be loaded before renderering the chart

Each env option will appear in a drop down along with "none".