Adding filtering capability to guitar tabs page

Hey Emil, see what you think of this. The tabs page is getting rather long, so I added a simple filtering mechanism to type in a textbox and have it filter the table. I've attached a GIF of it in action so you can see without too much fuss. I've put the JS in a separate file so we can easily use it on the bass tabs page should that start getting long.

Hope you like it, let me know if you'd like any changes or just aren't interested, I understand if you might not have expected or wanted changes outside of tabs.

![emilssearch](https://f.cloud.github.com/assets/93695/1146619/3ba2fbf4-1e74-11e3-8413-d6787fe871f3.gif)