componentize

Hi, I made your project a [component](https://github.com/component/component/wiki/Components).

I moved the minified js from build to a new "dist" directory, because the component build defaults to build/ and it's different from the standalone build so it needed a different place.
Now xgui.js and xgui.min.js standalones are built with "make dist" using a combination of the component tool and the builder you had and they're put in dist/.

So it's backwards compatible but now it's also ready to be installed and used with the component tool. In the future, the elements and some utils could be extracted into their own files or modules and required into the main.

Also, great work! I love how these look and play. I'm certainly going to be using them in a project soon-ish.