Pyglet backend emits an extra key press event when a 'text' key is pr…

…essed

The first keypress event will have text set to empty string. If the
key being pressed represents a character, a second event is emitted
which has the right text, and key set to None.

vispy/app/backends/pyglet.py

@@ -254,10 +254,21 @@ def on_key_press(self, key, modifiers):
         # Emit
         self._vispy_canvas.events.key_press(
                 key=self._processKey(key), 
-                text=text,
+                text='',  # Handlers that trigger on text wont see this event
                 modifiers=self._modifiers(modifiers),
             )
 
+
+    def on_text(self, text):
+        # Typically this is called after on_key_press and before 
+        # on_key_release
+        self._vispy_canvas.events.key_press(
+                key=None, # Handlers that trigger on key wont see this event
+                text=text,
+                modifiers=self._modifiers(),
+            )
+
+
     def on_key_release(self, key, modifiers):
         # Process modifiers
         if key in ( pyglet.window.key.LCTRL, pyglet.window.key.RCTRL,