Feature/style and add jquery

Hi, I made some changes you might want to add to this project:

![image 2014-09-05 at 12 22 04 pm](https://cloud.githubusercontent.com/assets/65846/4163401/adfd731c-34e6-11e4-8b59-96139a69e86a.png)

![screen shot 2014-09-06 at 07 40 21](https://cloud.githubusercontent.com/assets/65846/4174353/8213c2fe-3588-11e4-9337-fcb7518a13e1.png)


Features:
 - command history with up and down arrows
 - commands are cached in a cookie
 - basic type-colored output
 - run rake tasks the same way as in command line "rake ..."
 - remembers variables in one session (reload to clear context)
 - focus textarea on page load
 - catches syntax errors
 - moved pure JS to jQuery
 - moved js into files
 - added help command