Fixed #629 (timeout event of QTimer not present on Qt5) (#631)

In addition, the "destroyed" and "objectNameChanged" signals
were added (specifically to QObject).

The API binding for Qt5 was updated which adds some events.

scripts/mkqtdecl_common/cpp_parser_classes.rb

@@ -452,7 +452,7 @@ end
 
 module PExternBlock
   def cpp
-    self.get_cpp.collect do |d| 
+    (self.get_cpp || []).collect do |d| 
       if d.is_a?(CPPDeclaration)
         d.storage_class = :extern
       end