pressing Escape quits the program for now

Window.py

@@ -13,6 +13,7 @@ class Window:
         self.window.set_size_request(600, 500)
         self.window.set_title(title)
         self.window.connect("destroy", self.destroy_event)
+        self.window.connect("key-press-event", self.key_press_event)
 
         s = Sketch()
         l1 = Line(0, 1, 1, 1)
@@ -61,3 +62,8 @@ class Window:
 
     def destroy_event(self, widget, data=None):
         gtk.main_quit()
+
+    def key_press_event(self, widget, event, data=None):
+        if event.keyval == gtk.gdk.keyval_from_name("Escape"):
+            gtk.main_quit()
+        return False