Always default to http for IE when accessing cab file

Thanks for the great plugin!

I have been encountering the problem that I constantly get 404 errors on IE when using Soundmanager2.

It tries to access `download.macromedia.com/....` from the current url rather that using the absolute url.
eg. If my sire is hosted at `http://www.example.com/test`, it tries to access `http://www.example.com/download.macromedia.com/...` and spits out a 404 error.

Please do suggest if this is a valid fix and if refactoring is required.

Thanks