Cypclass test distutil & doctest: typecast operators

nogil_test/cypclass_test_typecast.pyx

+# mode: run
+# distutils: language=c++
+# distutils: extra_compile_args=-std=c++11
+# tag: cpp
+
 cdef cypclass SomeMemory:
     int a
 
@@ -21,6 +26,14 @@ cdef cypclass SomeWrapper:
         return self.m
 
 cpdef bag():
+  """
+  >>> bag()
+  -1
+  4294967295
+  True
+  3
+  False
+  """
   cdef SomeMemory o = SomeMemory()
   o.a = -1
   cdef SomeWrapper w = SomeWrapper(3)