Consider embedding layer names in a different way

[mimshwright]

Currently, layer names are embedded into the HTML as the first class in the list of classes. This seems like a decent idea, but for my project, I don't think it's going to work. Instead I'm going to create a different attribute called data-layer or possibly use the id.

Is this something that you would like for the main branch? And should it be an option perhaps that the user decides?