Add new global shortcut system backend for X11 and Windows

- Remove qxt
- Also create an option for enabled/disabling shortcuts through X11.

src/globalshortcuts/globalshortcutbackend.h

@@ -24,8 +24,12 @@
 #include "config.h"
 
 #include <stdbool.h>
-#include <QString>
+
+#include <QtGlobal>
 #include <QObject>
+#include <QPair>
+#include <QHash>
+#include <QString>
 
 class GlobalShortcuts;
 
@@ -41,15 +45,16 @@ class GlobalShortcutBackend : public QObject {
   bool Register();
   void Unregister();
 
-signals:
+ signals:
   void RegisterFinished(bool success);
 
  protected:
   virtual bool DoRegister() = 0;
   virtual void DoUnregister() = 0;
 
-  GlobalShortcuts* manager_;
+  GlobalShortcuts *manager_;
   bool active_;
+
 };
 
 #endif  // GLOBALSHORTCUTBACKEND_H