Updated kettu

Whew! Finally got round to making all those changes I promised :) . Lots of good bug fixes and new features. I've tried to stick to your coding styles and standards - let me know if anything's not up to scratch.

However, I do not know how to run or write the tests, so I have not changed them. For future reference, could you let me know how to run the tests and what framework/library they are written with? Also be warned that I have not tested the changes at all on mobile.

Some other misc stuff: the progress bar uses a background url image - why? Since it's just a single color anyways, why not just declare the color? kettu on mobile is unusably slow for me with more than one torrent - would be great if you could look into some sort of optimizing, and only update the parts of the DOM that you absolutely have to. Also, is an update checker built in? Maybe you can have it check for updates (using github) when you load the page and display a message with '#flash'. Finally, I noticed that you have a backbone branch on your repo; I recently came across http://angularjs.org/ and it seems to be the one MVC framework (if you can call it that) to rule them all. And it's built by Googlers, so it's gotta be good :) . Maybe you can look into building an AngularJS version - seems like it would be somewhat easier to maintain.