Enable parallel.js to transmit transferable objects

This only works in a client side setting because node.js transmits it's values via a socket and therefore string based.

This is necessary to enable developers to transmit Uint8Array contents of a canvas for example. This would be painfully slow to transmit with JSON.

I didn't have anything to test with node.js, although I tried to change as little as possible in that respect.
As for the client side: I added a new example to the index.html file and tested all the available examples successfully.