Use of MessageChannel
wip
Communication inside a window works. Lets try between iframes now
WIP - Working sample

* Multiple channels can be created and used to communicate
* No good way to manage the port message queue for the moment

Problems:
* EventTarget support (chrome and safari ko, firefox ok)
* CustomEvent support?
* window.postMessage signature that would need to be overwritten (can
not pass "fake "ports)
Add .gitignore
Simple implemenation for MessagePort.start
Clean code - use of messageEvent.origin
getPort uses messageEvent to retrieve currentTarget and destinationUrl
Rename some variables
Put sample code outside the test suite
Add tests
Make sample project host agnostic
the EventTarget interface's implementation has a  as described in the specs
Update sample project to use the correct EventTarget implementation
Use of `MessageChannel.decodeEvent` in the message handler
Add README