Binding options can now be customized for MASShortcutBinder.

This makes it possible to customize the way the shortcuts are stored
in user defaults. The default options call for the keyed archiver
transformer, deserializing the shortcuts from NSData.
Added a custom transformer to store shortcuts as dictionaries.

The MASDictionaryTransformer class is used to save shortcuts to
user defaults (and load them back) using a simple dictionary. The
value stored in the user defaults looks like this:

$ defaults read com.shpakovski.mac.Demo
{
    MASDemoShortcut =     {
        keyCode = 15;
        modifierFlags = 1048576;
    };
    …
}

This storage format has got the distinct advantage of being compatible
with the format used by Shortcut Recorder. In order to use it, you
have to set proper binding options for MASShortcutBinder and the
recorder control (MASShortcutView).