* Migrate set() and frozenset() from the sandbox.

* Install the unittests, docs, newsitem, include file, and makefile update.
* Exercise the new functions whereever sets.py was being used.

Includes the docs for libfuncs.tex.  Separate docs for the types are
forthcoming.

Include/setobject.h

@@ -0,0 +1,26 @@
+
+/* Set object interface */
+
+#ifndef Py_SETOBJECT_H
+#define Py_SETOBJECT_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+This data structure is shared by set and frozenset objects.
+*/
+
+typedef struct {
+	PyObject_HEAD
+	PyObject *data;
+	long hash;	/* only used by frozenset objects */
+} PySetObject;
+
+PyAPI_DATA(PyTypeObject) PySet_Type;
+PyAPI_DATA(PyTypeObject) PyFrozenSet_Type;
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !Py_SETOBJECT_H */