add_accelerator
Description:
public void add_accelerator (string accel_signal, AccelGroup accel_group, uint accel_key, ModifierType accel_mods, AccelFlags accel_flags)
  
  Installs an accelerator for this this in accel_group that causes accel_signal to be
       emitted if the accelerator is activated.
 The accel_group needs to be added to the widget’s toplevel via 
      add_accel_group, and the signal must be of type 
      g_signal_action. Accelerators added through this function are not user changeable during runtime. If you want 
      to support accelerators that can be changed by the user, use add_entry
       and set_accel_path or 
      set_accel_path instead.
Parameters:
| this | widget to install an accelerator on | 
| accel_signal | widget signal to emit on accelerator activation | 
| accel_group | accel group for this widget, added to its toplevel | 
| accel_key | GDK keyval of the accelerator | 
| accel_mods | modifier key combination of the accelerator | 
| accel_flags | flag accelerators, e.g. gtk_accel_visible |