vendor/emmet.js
function() {
			if (!this.children.length)
				return null;
				
			var deepestChild = this;
			while (deepestChild.children.length) {
				deepestChild = _.last(deepestChild.children);
			}
			
			return deepestChild;
		}
function() {
			if (!this.children.length)
				return null;
				
			var deepestChild = this;
			while (deepestChild.children.length) {
				deepestChild = _.last(deepestChild.children);
			}
			
			return deepestChild;
		}
Returns latest and deepest child of current tree
@returns {AbbreviationNode}