message: add pop and shift scalar from list
diff: @@ -452,6 +452,20 @@ export namespace NBT {
  return TagList.prototype.push.apply(this, scalars);
  }
  + popScalar<S extends ScalarTypes>(this: TagList<TagScalar<S>> & this): S | undefined {
  + let value: TagScalar<S> | undefined = this.pop();
  + if (value === undefined)
  + return undefined;
  + return value.value;
  + }
  +
  + shiftScalar<S extends ScalarTypes>(this: TagList<TagScalar<S>> & this): S | undefined {
  + let value: TagScalar<S> | undefined = this.shift();
  + if (value === undefined)
  + return undefined;
  + return value.value;
  + }
  +
  unshiftScalar<S extends ScalarTypes>(this: TagList<TagScalar<S>> & this, ...items: S[]): number {
  let scalars: T[] = [];
  for (let i: number = 0; i < items.length; i++) {
  