message: Add `TileMap::size()` method
diff: @@ -63,6 +63,7 @@ public:
  int edgeLength() const { return mEdgeLength; }
  int width() const { return mWidth; }
  int height() const { return mHeight; }
  + NAS2D::Vector<int> size() const { return {mWidth, mHeight}; }
  int currentDepth() const { return mCurrentDepth; }
  void currentDepth(int i) { mCurrentDepth = std::clamp(i, 0, mMaxDepth); }
  