Add test to see if HTML shim is needed

[Tokimon]

This has a relevance if the detection is not used with Modernizr.
Generally you can just include the HTML5 shiv from a CDN and don't have to worry about it, but to avoid further HTTP requests i could be interesting to include.
It is a bit dodgy as a test, but I'll leave it in.

[Tokimon]

Should be as simple as 'hidden' in document.createElement('a') (that is how the HTML5Shiv is doing it)