getEventKey implementation inconsistent with DOM3 spec / Firefox implementation

There are some inconsistencies between `getEventKey` and the DOM3 keyboard event spec (as well as what Firefox has implemented): - `key` property is not correctly set for printable characters on `keydown` and `keyup` events. This works properly in Firefox, and my interpretation of the standard is that Firefox's behaviour is correct here. From the spec: _If the key generates a printable character, and there exists an appropriate Unicode code point, then the KeyboardEvent.key attribute must be a string consisting of the char value of that character._ - Enter key only fires keydown in Firefox, but fires both keydown and keypress in Chrome. This should be consistent across browsers - CapsLock key only fires keydown when it is toggled on. When caps lock is toggled from on to off, no keydown event is fired (this may be a browser limitation in Chrome) Repro: Test this page in Firefox and compare the result to Chrome: http://jsfiddle.net/63ycmLhe/1/