All objects should return self on serialize

svn: r19687

src/gen/lib/styledtext.py

@@ -287,6 +287,7 @@ class StyledText(object):
             stt = StyledTextTag()
             stt.unserialize(tag)
             self._tags.append(stt)
+        return self
     
     def get_tags(self):
         """Return the list of formatting tags.
@@ -315,4 +316,4 @@ if __name__ == '__main__':
     C = C.replace('X', StyledText('_'))
     A = A + B
 
-    print A
+    print A