* 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.
diff --git a/Lib/_strptime.py b/Lib/_strptime.py
index 4746544..df04674 100644
--- a/Lib/_strptime.py
+++ b/Lib/_strptime.py
@@ -16,7 +16,6 @@
 from re import compile as re_compile
 from re import IGNORECASE
 from datetime import date as datetime_date
-from sets import ImmutableSet as sets_ImmutableSet
 try:
     from thread import allocate_lock as _thread_allocate_lock
 except:
@@ -165,11 +164,11 @@
             time.tzset()
         except AttributeError:
             pass
-        no_saving = sets_ImmutableSet(["utc", "gmt", time.tzname[0].lower()])
+        no_saving = frozenset(["utc", "gmt", time.tzname[0].lower()])
         if time.daylight:
-            has_saving = sets_ImmutableSet([time.tzname[1].lower()])
+            has_saving = frozenset([time.tzname[1].lower()])
         else:
-            has_saving = sets_ImmutableSet()
+            has_saving = frozenset()
         self.timezone = (no_saving, has_saving)