Polyfill function.bind take 3

The current score: function.prototype.bind 2 patrick 0

Third attempt at polyfilling `.bind();` to open up our JS application to a wider audience. As per @gklopper advice I've wrapped it in a switch this time so very easy to revert if we see the Omniture confidence bombing out again.

/cc @rich-nguyen @ironsidevsquincy