Merge in the refactor from earlier.

gui.hpp

@@ -46,8 +46,6 @@ class GUI {
   sf::Font $font;
   sf::Text $ui_text;
   sf::Text $map_text;
-  bool $shake_it = false;
-  bool $burn_baby_burn = false;
   std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> $converter;
   sf::RenderWindow $window;
   Screen $screen;
@@ -63,11 +61,12 @@ public:
   sf::Color color(int val);
   void create_renderer();
   void render_scene();
-  void handle_events();
+  bool handle_events();
   void draw_screen(bool clear=true, float map_off_x=0.0f, float map_off_y=0.0f);
   void shake();
   void burn();
   void configure_world();
+  void run_systems();
 
   int main();
 };