MOST IMPORTANT PR EVER!1! MERGE NAAAOOOWW

add theme color, for colorful tabs in mobile Chrome

Further reading: http://updates.html5rocks.com/2014/11/Support-for-theme-color-in-Chrome-39-for-Android

## Examples

![screenshot_2014-12-05-22-26-42](https://cloud.githubusercontent.com/assets/474248/5323287/b0d26676-7cce-11e4-9146-e7f532dda4d9.png)
![screenshot_2014-12-05-22-26-52](https://cloud.githubusercontent.com/assets/474248/5323288/b0d32674-7cce-11e4-9d08-5a2edad920b2.png)