Avoid conflicts with existing stylesheets by adding specifity to css files.

This pr makes the provided css files more usable straight out of the box (since we can assume that a lot of developers may want to use grande.js as a component rather that a whole body element). Added specifity avoids conflicts with existing stylesheets and obliterates the need of !important flags in rules.

I also moved the body rules from editor.css to index.html since they likely exist for demo purposes only.

The css is an output from .less files with nested rules. I have this build process available in a separate branch if you want to have a look at it (build-process-ideas). There's more than that going on in that branch because I was thinking of a way to release grande.js as a minified and optimized bundle and alternatively give developers the chance to include the .less files directly into their grunt workflow (at least that is my use case). This effectively makes grande.js styles less opinionated and easier to customize.