Suppress some pylint issues

The overrides are necessary to make the multicommands/widgets behave
well.

topydo/lib/MultiCommand.py

@@ -35,6 +35,7 @@ class MultiCommand(ExpressionCommand):
         self.is_expression = False
         self.multi_mode = True
 
+    # pylint: disable=no-self-use
     def get_flags(self):
         """ Default implementation of getting specific flags. """
         return ("", [])

topydo/ui/columns/TodoListWidget.py

@@ -207,6 +207,7 @@ class TodoListWidget(urwid.LineBox):
                                    p_row,
                                    p_focus)
 
+    # pylint: disable=no-self-use
     def selectable(self):
         return True
 

topydo/ui/columns/TodoWidget.py

@@ -117,13 +117,15 @@ class TodoWidget(urwid.WidgetWrap):
 
         super().__init__(self.widget)
 
-    def keypress(self, p_size, p_key):
+    # pylint: disable=no-self-use
+    def keypress(self, _, p_key):
         """
         Override keypress to prevent the wrapped Columns widget to
         receive any key.
         """
         return p_key
 
+    # pylint: disable=no-self-use
     def selectable(self):
         # make sure that ListBox will highlight this widget
         return True