Added HUD widgets, make Boot and Close use button_up instead of button_down

lib/hud.rb

@@ -0,0 +1,23 @@
+class IMICFPS
+  class HUD
+    def initialize(player)
+      @ammo = AmmoWidget.new({ player: player })
+      @radar = RadarWidget.new({ player: player })
+      @health = HealthWidget.new({ player: player })
+
+      @hud_elements = [
+        @ammo,
+        @radar,
+        @health,
+      ]
+    end
+
+    def draw
+      @hud_elements.each(&:draw)
+    end
+
+    def update
+      @hud_elements.each(&:update)
+    end
+  end
+end