Fix NavBar color in IE

Fix #1 mentioned issue: navbar menu crumble in IE.

Related post with this IE issue:

[Twitter Bootstrap - nav bar issues in internet explorer](http://stackoverflow.com/questions/9780464/twitter-bootstrap-nav-bar-issues-in-internet-explorer)

[Twitter BootStrap NavBar Color in IE8/9](http://www.anujgakhar.com/2012/09/05/twitter-bootstrap-navbar-color-in-ie89/)