Search: Initial support for Python 3.x

(cherry picked from commit f4c2fdd2fd)

src/misc.h

@@ -151,6 +151,7 @@ public:
   // Get screen center
   static QPoint screenCenter(QWidget *win);
 #endif
+  static int pythonVersion();
   static QString searchEngineLocation();
   static QString BTBackupLocation();
   static QString cacheLocation();