message: Add TileMap::mouseTilePosition() method returning MapCoordinate
diff: @@ -59,6 +59,7 @@ public:
  bool tileHighlightVisible() const;
  NAS2D::Point<int> tileMouseHover() const { return mMapHighlight; }
  + MapCoordinate mouseTilePosition() const { return {mMapHighlight, mCurrentDepth}; }
  const Point2dList& mineLocations() const { return mMineLocations; }
  void removeMineLocation(const NAS2D::Point<int>& pt);
  