Adding additional cryptographic base classes

This change adds two additional abstract base classes for the Pie
ManagedObject object hierarchy: CryptographicObject and Key. Test suites
are provided for each base class, using a dummy subclass of each for
testing. The object test suite package structure is also modified to
collect all ManagedObject subclass tests in one package.

kmip/tests/unit/pie/objects/__init__.py

@@ -0,0 +1,14 @@
+# Copyright (c) 2015 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.