add swig::PyItem and all the helper code

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk/SWIG@7787 626c5289-ae23-0410-ae9c-e8d60b6d4f22

Examples/test-suite/python/li_std_set_runme.py

@@ -82,3 +82,15 @@ if m.value() != "c":
 
 
 
+s = pyset()
+s.insert((1,2))
+s.insert(1)
+s.insert("hello")
+
+
+sum = ()
+for i in s:
+    sum += (i,)
+
+if sum != (1, 'hello', (1, 2)):
+    raise RuntimeError