Redraw the screen in more elegant way after 'e'

Thanks to @bram85 for the idea.

topydo/ui/Main.py

@@ -258,6 +258,7 @@ class UIApplication(CLIApplicationBase):
         no_output = lambda _: None
         urwid.connect_signal(todolist, 'execute_command',
                              lambda cmd: self._execute_handler(cmd, no_output))
+        urwid.connect_signal(todolist, 'refresh', self.mainloop.screen.clear)
 
         options = self.columns.options(
             width_type='given',

topydo/ui/TodoListWidget.py

@@ -43,7 +43,7 @@ class TodoListWidget(urwid.LineBox):
 
         super().__init__(pile)
 
-        urwid.register_signal(TodoListWidget, ['execute_command'])
+        urwid.register_signal(TodoListWidget, ['execute_command', 'refresh'])
 
     @property
     def view(self):
@@ -134,7 +134,7 @@ class TodoListWidget(urwid.LineBox):
         elif p_key == 'e':
             self._edit_selected_item()
             # force screen redraw after editing
-            return self.listbox.keypress(p_size, 'ctrl l')
+            urwid.emit_signal(self, 'refresh')
         elif p_key == 'r':
             self.keystate = 'r'
         elif p_key == 'u':