message: Simplify calculation of TileMap::tileMouseHover()
  This becomes easier once the Point/Vector distinction is resolved.
diff: @@ -50,10 +50,7 @@ public:
  void centerMapOnTile(Tile*);
  bool tileHighlightVisible() const;
  -
  - int tileMouseHoverX() const { return mMapHighlight.x + mMapViewLocation.x(); }
  - int tileMouseHoverY() const { return mMapHighlight.y + mMapViewLocation.y(); }
  - NAS2D::Point<int> tileMouseHover() const { return NAS2D::Point{tileMouseHoverX(), tileMouseHoverY()}; }
  + NAS2D::Point<int> tileMouseHover() const { return mMapViewLocation + mMapHighlight; }
  const Point2dList& mineLocations() const { return mMineLocations; }
  void removeMineLocation(const NAS2D::Point<int>& pt);
  