Ported to Usercss

[TrakJohnson]

Ported the stylesheet to the Usercss format.

This makes the development easier (after building changes are reflected instantly, no need to copy paste or even reload the page), offers many more options in terms of customization and allows the use of preprocessors. Also, it removes the need for a json file.

Also changed the border of embedded tables in docs from black to grey.

[YodaEmbedding]

Thanks; I always wanted to move over to a more automated build/test method.