Right Click Menu Shortcut Keys

Since GNOME Do is intended to improve user experience especially on the GNOME desktop, it would be beneficial to have right click menu shortcut keys. Most (if not all) GNOME applications have shortcut keys for their menus and right click menus. GNOME Do should not be an exception. This application is often right clicked as it has a good number of operations its user can choose whenever an application icon is right clicked. A good use case is whenever a user wants to minimize an application, the application entry on the window list applet on the GNOME panel is right clicked and the user can simply press "n" to minimize the window. This makes operations on GNOME Do faster.