Adding support for the RekeyKeyPair operation

This change adds support for the ReKeyKeyPair operation, adding in
required KMIP objects and updating the KMIP client. Minor changes to the
server are included in preparation for future changes. The unit test
suite has been updated accordingly.

kmip/core/misc.py

@@ -0,0 +1,23 @@
+# Copyright (c) 2014 The Johns Hopkins University/Applied Physics Laboratory
+# All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+from kmip.core import enums
+from kmip.core import primitives
+
+
+class Offset(primitives.Interval):
+
+    def __init__(self, value=None, tag=enums.Tags.OFFSET):
+        super(Offset, self).__init__(value, tag)