wasp: draw565: Allow the drawing context to be reset

The main reason to reset the drawing context is so that it can be reset
before we call foreground() on an application.

wasp/draw565.py

@@ -78,6 +78,10 @@ class Draw565(object):
         and 24 pt Sans Serif text.
         """
         self._display = display
+        self.reset()
+
+    def reset(self):
+        """Restore the default colour and font."""
         self.set_color(0xffff)
         self.set_font(fonts.sans24)
 

wasp/wasp.py

@@ -130,6 +130,7 @@ class Manager():
 
         self.app = app
         watch.display.mute(True)
+        watch.drawable.reset()
         app.foreground()
         watch.display.mute(False)