Replace server/browser transport layer with ubf bus.

This is the branch belonging to issue #793 

The new transport layer completely replaces the old query-encoded web socket, comet and postback interface.

It also changes the way data is sent back to the browser after a (hidden) form post for uploading files.

For testing you might need to include `lib/js/modules/ubf.js` in your project.

In my testing this change works as advertised. 
Due to the complexity I am certain that there will be some issues, so please test with your setup.
Maybe it's nice to tell how other kinds of data (e.g. non-javascript data) can be sent to the client and how the client will receive this?