code: function(child, position) {
  			child = child || new AbbreviationNode();
  			child.parent = this;
  			
  			if (typeof position === 'undefined') {
  				this.children.push(child);
  			} else {
  				this.children.splice(position, 0, child);
  			}
  			
  			return child;
  		}
docs: Adds passed node as child or creates new child
  @param {AbbreviationNode} child
  @param {Number} position Index in children array where child should
  be inserted
  @return {AbbreviationNode}