KeyEvent class

A custom KeyboardEvent that attempts to eliminate cross-browser inconsistencies, and also provide both keyCode and charCode information for all key events (when such information can be determined).

KeyEvent tries to provide a higher level, more polished keyboard event information on top of the "raw" KeyboardEvent.

The mechanics of using KeyEvents is a little different from the underlying KeyboardEvent. To use KeyEvents, you need to create a stream and then add KeyEvents to the stream, rather than using the EventTarget.dispatchEvent. Here's an example usage:

// Initialize a stream for the KeyEvents:
var stream = KeyEvent.keyPressEvent.forTarget(document.body);
// Start listening to the stream of KeyEvents.
stream.listen((keyEvent) =>
    window.console.log('KeyPress event detected ${keyEvent.charCode}'));
...
// Add a new KeyEvent of someone pressing the 'A' key to the stream so
// listeners can know a KeyEvent happened.
stream.add(new KeyEvent('keypress', keyCode: 65, charCode: 97));

This class is very much a work in progress, and we'd love to get information on how we can make this class work with as many international keyboards as possible. Bugs welcome!