code: function (change) {
  			if (this.compoundChange) {
  				this.compoundChange.add(change);
  			} else {
  				var length = this.stack.length;
  				this.stack.splice(this.index, length-this.index, change);
  				this.index++;
  				if (this.stack.length > this.size) {
  					this.stack.shift();
  					this.index--;
  				}
  			}
  		}
docs: Adds a change to the stack.
  
  @param change the change to add.