Clean up the GUI some by moving the map_view out into its own file.

map_view.hpp

@@ -0,0 +1,20 @@
+#pragma once
+#include "panel.hpp"
+#include <ftxui/dom/canvas.hpp>
+#include "levelmanager.hpp"
+
+using ftxui::Canvas;
+
+namespace gui {
+  class MapViewUI : public Panel {
+    public:
+      Canvas $canvas;
+      GameLevel $level;
+
+      MapViewUI(GameLevel &level);
+      void create_render();
+      void resize_canvas();
+      void draw_map();
+      void update_level(GameLevel &level);
+  };
+}