[Interchange] Use RegExp When Parsing Data Attribute Data

There is an issue when using assets (images or html) that contain a `,` in the url. For example: `http://res.cloudinary.com/demo/image/upload/w_800,h_500,c_fit/sample.jpg`. Interchange will mutilate this url and never actually load the asset.

This branch splits using a RegExp instead of just on `,`. This seems to handle this case very well, and loads assets appropriately.