Really crappy minimap now displays.

tilemap.cpp

@@ -73,3 +73,21 @@ bool TileMap::INVARIANT() {
   dbc::check(matrix::width($tile_ids) == $width, "$tile_ids has wrong width");
   return true;
 }
+
+std::wstring TileMap::minimap(size_t x, size_t y) {
+  string result;
+
+  for(matrix::box it{$tile_ids, x, y, 5}; it.next();) {
+    const TileCell &cell = $display[it.y][it.x];
+    if(it.x == x && it.y == y) {
+      result += "@";
+    } else {
+      result += cell.display;
+    }
+
+    if(it.x == it.right - 1) result += "\n";
+  }
+
+  std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> $converter;
+  return $converter.from_bytes(result);
+}