Browser detection

Fixes #223 by replacing the current detection with the
https://github.com/ded/bowser library. The previous detection is no
longer used on http://www.quirksmode.org/js/detect.html from which it
was based and would have been awkward to fit IE11 detection into this
approach of searching through object values.

Please note that some of the browser names in bower differ from those
used previously. For example "Explorer" is now "Internet Explorer".