Make |EditingContext.prototype.splitNode(element, refChild)| not to create new element if |refChild| is first child of |element| for fixing "creatLink.style.6.css"
Example: "<i>|after</i>" => <i>after</i>
Introduce |EditingContext.prototype.setUpEffectiveNodesWithSplitter| and use more restriced types for |EditingContext.prototype.split{Node,Tree}|.
Introduce |EditingStyle.prototype.applyInheritedStyle()|.
createLink: Changes to pass layout test "editing/execCommand/toggle-link-win.html".