Fix: 'None' value for keybindings breaks editor

The bug: Gtk.accelerator_parse throws an error if the arg is None.
This means that if one keybinding is set to None, it is impossible to
set any new keybinding.

terminatorlib/prefseditor.py

@@ -1738,10 +1738,13 @@ class PrefsEditor:
 
         accel = Gtk.accelerator_name(key, mods)
         current_binding = liststore.get_value(liststore.get_iter(path), 0)
+        parsed_accel = Gtk.accelerator_parse(accel)
 
         duplicate_bindings = []
         for conf_binding, conf_accel in self.config["keybindings"].items():
-            parsed_accel = Gtk.accelerator_parse(accel)
+            if conf_accel is None:
+                continue
+
             parsed_conf_accel = Gtk.accelerator_parse(conf_accel)
 
             if (

terminatorlib/window.py

@@ -130,7 +130,7 @@ class Window(Container, Gtk.Window):
 
         # Attempt to grab a global hotkey for hiding the window.
         # If we fail, we'll never hide the window, iconifying instead.
-        if self.config['keybindings']['hide_window'] != '':
+        if self.config['keybindings']['hide_window'] not in ('', None):
             if display_manager() == 'X11':
                 try:
                     self.hidebound = Keybinder.bind(