Update modernizr

Hi,

your used version of Modernizr (1.6) triggers an GPU switch on every page load on macbooks with two gpus - see https://github.com/Modernizr/Modernizr/issues/1341

I looked around and found no usage of special Modernizr tests, so I created a custom build that only includes the core, html5shiv and the css classes.

Big thanks for the project :)
~robbi5