Short description and demo link

[fenimore]

Hey I realize there is a demo link in the readme, but Github has a special place, on the top of the page near the title of the readme, for adding a short description and a link -- I often search here for links to documentation or demos that I expect from a project, and all your repos have this blank. I also recommend the short description so that way your github profile will have not just slim but a little tagline to describe what slim is. 😄