browser-specific header fixed.

> Warning: X-UA-Compatible is a browser-specific HTTP header.
> *[html5.validator.nu]*

Before:
![][1]
After:
![][2]

[1]: http://i.imgur.com/8yVh3PR.png
[2]: http://i.imgur.com/Ro6HC3A.png
[html5.validator.nu]: http://html5.validator.nu/