Restructure comparison dramatically. There is no longer a default

*ordering* between objects; there is only a default equality test
(defined by an object being equal to itself only).  Read the comment
in object.c.  The current implementation never uses a three-way
comparison to compute a rich comparison, but it does use a rich
comparison to compute a three-way comparison.  I'm not quite done
ripping out all the calls to PyObject_Compare/Cmp, or replacing
tp_compare implementations with tp_richcompare implementations;
but much of that has happened (to make most unit tests pass).

The following tests still fail, because I need help deciding
or understanding:

test_codeop -- depends on comparing code objects
test_datetime -- need Tim Peters' opinion
test_marshal -- depends on comparing code objects
test_mutants -- need help understanding it

The problem with test_codeop and test_marshal is this: these tests
compare two different code objects and expect them to be equal.
Is that still a feature we'd like to support?  I've temporarily
removed the comparison and hash code from code objects, so they
use the default (equality by pointer only) comparison.

For the other two tests, run them to see for yourself.
(There may be more failing test with "-u all".)

A general problem with getting lots of these tests to pass is
the reality that for object types that have a natural total ordering,
implementing __cmp__ is much more convenient than implementing
__eq__, __ne__, __lt__, and so on.  Should we go back to allowing
__cmp__ to provide a total ordering?  Should we provide some other
way to implement rich comparison with a single method override?
Alex proposed a __key__() method; I've considered a __richcmp__()
method.  Or perhaps __cmp__() just shouldn't be killed off...

Lib/xmlrpclib.py

@@ -282,56 +282,9 @@ class Fault(Error):
 # @param value A boolean value.  Any true value is interpreted as True,
 #              all other values are interpreted as False.
 
-if _bool_is_builtin:
-    boolean = Boolean = bool
-    # to avoid breaking code which references xmlrpclib.{True,False}
-    True, False = True, False
-else:
-    class Boolean:
-        """Boolean-value wrapper.
-
-        Use True or False to generate a "boolean" XML-RPC value.
-        """
-
-        def __init__(self, value = 0):
-            self.value = operator.truth(value)
-
-        def encode(self, out):
-            out.write("<value><boolean>%d</boolean></value>\n" % self.value)
-
-        def __cmp__(self, other):
-            if isinstance(other, Boolean):
-                other = other.value
-            return cmp(self.value, other)
-
-        def __repr__(self):
-            if self.value:
-                return "<Boolean True at %x>" % id(self)
-            else:
-                return "<Boolean False at %x>" % id(self)
-
-        def __int__(self):
-            return self.value
-
-        def __nonzero__(self):
-            return self.value
-
-    True, False = Boolean(1), Boolean(0)
-
-    ##
-    # Map true or false value to XML-RPC boolean values.
-    #
-    # @def boolean(value)
-    # @param value A boolean value.  Any true value is mapped to True,
-    #              all other values are mapped to False.
-    # @return xmlrpclib.True or xmlrpclib.False.
-    # @see Boolean
-    # @see True
-    # @see False
-
-    def boolean(value, _truefalse=(False, True)):
-        """Convert any Python value to XML-RPC 'boolean'."""
-        return _truefalse[operator.truth(value)]
+boolean = Boolean = bool
+# to avoid breaking code which references xmlrpclib.{True,False}
+True, False = True, False
 
 ##
 # Wrapper for XML-RPC DateTime values.  This converts a time value to
@@ -371,10 +324,15 @@ class DateTime:
             value = time.strftime("%Y%m%dT%H:%M:%S", value)
         self.value = value
 
-    def __cmp__(self, other):
+    def __eq__(self, other):
         if isinstance(other, DateTime):
             other = other.value
-        return cmp(self.value, other)
+        return self.value == other
+
+    def __ne__(self, other):
+        if isinstance(other, DateTime):
+            other = other.value
+        return self.value != other
 
     ##
     # Get date/time value.
@@ -432,10 +390,15 @@ class Binary:
     def __str__(self):
         return self.data or ""
 
-    def __cmp__(self, other):
+    def __eq__(self, other):
         if isinstance(other, Binary):
             other = other.data
-        return cmp(self.data, other)
+        return self.data == other
+
+    def __ne__(self, other):
+        if isinstance(other, Binary):
+            other = other.data
+        return self.data != other
 
     def decode(self, data):
         self.data = base64.decodestring(data)