Adding support for special-key handler in dialog field definition

[Garry Yao]

It's a common use case for user to define custom logic as handler for special-keystroke on dialog field, a example for this would be 'ENTER' key by default is handled as ok and close for the dialog, whereas in find/replace dialog it actually should mean by perform next search, and consider 'ESC' as one of other cases and on. After confirm with Martin, we'll introduce special key handlers in element definition API in simple form of:

{
	type: 'text',
	id: 'findReplaceTxt',
	accessKey: 'F',
	onEnterKey: function(evt)
	{
	  //do find 
	}
}

Other special keys could be defined gradually same as the onEnterKey handler later when necessary.

[Garry Yao]

Fix extra comma

[Garry Yao]

Initiate with two keystroke:

• Enter
• Ctrl-Enter

[Frederico Caldeira Knabben]

We should be reviewing the dialog system in the near future, so this ticket could be considered at that point.

[Frederico Caldeira Knabben]

Milestone CKEditor 3.x deleted

[Frederico Caldeira Knabben]

Better to have a generic "onKey" event handler at this point, which can handle any kind of key. It should work like the "key" event fired on the editor, passing the keystroke to the handler.