Topic Jumper

Adds a widget to the progress bar to jump to specific posts.

Live demo: https://forum.riking.org/t/how-not-to-write-a-technical-book/571/44

The styling could really be improved - any tips @awesomerobot?
I finally got it looking almost the same on all 3 major browsers.

Chrome:
> ![image](https://cloud.githubusercontent.com/assets/627891/3086674/f2c24f2e-e53e-11e3-9586-39a2775ed527.png)


IE: 
> ![image](https://cloud.githubusercontent.com/assets/627891/3086665/98fa6c06-e53e-11e3-895a-a86bf72ffbd7.png)

FF:
> ![image](https://cloud.githubusercontent.com/assets/627891/3086699/fee50502-e53f-11e3-84ea-563c4a72fe0b.png)