Investigate complex class names

[gaku-sei]

So far, in order to keep it fast, we don't parse files provided to the style-validate binary. It works well with HTML files and some other files we're using in other projects but parsing complex class names like className={isDisabled ? "disabled" : "active"} is a legitimate use case.

Let's first try to use the current engine with regexes, and if it doesn't work we'll have to provide a more powerful parser.

Also, we could use duktape or v8 in order to support scripting in javascript, that would keep the codebase as is, but it might come with a big impact on performances, especially on large projects with +5.000 files.