Use the __xname__ attribute as the title for callable attributes

(falling back to __name__, if __xname__ doesn't exist).

IPython/Extensions/ipipe.py

@@ -374,7 +374,7 b' def _attrname(name):'
     elif isinstance(name, basestring):
         return name
     elif callable(name):
-        return name.__name__
+        return getattr(name, "__xname__", name.__name__)
     else:
         return str(name)