Add optional docstrings to member descriptors.  For backwards
compatibility, this required all places where an array of "struct
memberlist" structures was declared that is referenced from a type's
tp_members slot to change the type of the structure to PyMemberDef;
"struct memberlist" is now only used by old code that still calls
PyMember_Get/Set.  The code in PyObject_GenericGetAttr/SetAttr now
calls the new APIs PyMember_GetOne/SetOne, which take a PyMemberDef
argument.

As examples, I added actual docstrings to the attributes of a few
types: file, complex, instance method, super, and xxsubtype.spamlist.

Also converted the symtable to new style getattr.
diff --git a/Objects/frameobject.c b/Objects/frameobject.c
index fd9a4e2..cb7e80a 100644
--- a/Objects/frameobject.c
+++ b/Objects/frameobject.c
@@ -10,7 +10,7 @@
 
 #define OFF(x) offsetof(PyFrameObject, x)
 
-static struct memberlist frame_memberlist[] = {
+static PyMemberDef frame_memberlist[] = {
 	{"f_back",	T_OBJECT,	OFF(f_back),	RO},
 	{"f_code",	T_OBJECT,	OFF(f_code),	RO},
 	{"f_builtins",	T_OBJECT,	OFF(f_builtins),RO},