Add IE 11 detection to the browsehappy.org API

[blobaugh]

With Internet Explorer 11 Microsoft has changed how the user agent is presented. Now instead of any mention of IE in the UA apps are supposed to refer to the Trident version number. This patch adds the ability to the API

See:
User Agent Changes ​http://msdn.microsoft.com/en-us/library/ie/hh869301%28v=vs.85%29.aspx
Understanding the User Agent ​http://msdn.microsoft.com/en-us/library/ie/ms537503%28v=vs.85%29.aspx

[blobaugh]

Adds support for IE 11 User Agent string

[Otto42]

In 717:

Add support for IE-11/Trident. props blobaugh, fixes #416