Sliding tab Implementation

Okay. This is huge. I am not even sure whether you'll like this or not. 

I implemented (copy and modified) Google I/O alike Sliding Tab. Here's a screenshot. 

![sliding_bum](https://cloud.githubusercontent.com/assets/275120/4461706/9f84399e-48bc-11e4-8652-b98feb96fa46.png)


Yup. That's a lot of "copy" and "paste" codes. Please pull the PR and you might want to see how it's alike. 

Oh My God. My laptop battery is dying and I forgot my charger at office. :scream: