Fixed key binding reset key

Fixed issue #131
The reset key binding to default values key would remove all bindings insted of setting them to the default values.
This commit fixes that by reloading the default vals.

mcomix/mcomix/keybindings.py

@@ -135,6 +135,19 @@ def clear_all(self):
         self._action_to_callback = {}
         self._action_to_bindings = defaultdict(list)
         self._binding_to_action = {}
+
+        stored_action_bindings = keybindings_map.DEFAULT_BINDINGS.copy()
+
+        for action in keybindings_map.BINDING_INFO.keys():
+            if action in stored_action_bindings:
+                bindings = [
+                    Gtk.accelerator_parse(keyname)
+                    for keyname in stored_action_bindings[action] ]
+                self._action_to_bindings[action] = bindings
+                for binding in bindings:
+                    self._binding_to_action[binding] = action
+            else:
+                self._action_to_bindings[action] = []
 
     def execute(self, keybinding):
         ''' Executes an action that has been registered for the