Add Shortcuts preferences tab (Name not working)

rtgui/preferences.h

@@ -297,6 +297,7 @@ class Preferences final :
     Gtk::ScrolledWindow *swColorMan;
     Gtk::ScrolledWindow *swBatchProc;
     Gtk::ScrolledWindow *swPerformance;
+    Gtk::ScrolledWindow *swShortcuts;
     Gtk::ScrolledWindow *swSounds;
 
     Gtk::Widget *getGeneralPanel();
@@ -308,6 +309,7 @@ class Preferences final :
     Gtk::Widget *getBatchProcPanel();
     Gtk::Widget *getPerformancePanel();
     Gtk::Widget *getSoundsPanel();
+    Gtk::Widget *getShortcutsPanel();
 
 public:
     explicit Preferences (RTWindow *rtwindow);