Add request and response payloads for the DeriveKey operation

This change adds request/response payloads for the DeriveKey
operation, updating the payload factories to support DeriveKey.
Unit tests for the payloads and payload factories are included.
The inequality operator was also added to the TemplateAttribute
struct to support the DeriveKey payload unit tests; differences
in Python2.7 and 3+ led to comparison failures.

kmip/core/objects.py

@@ -947,6 +947,12 @@ class TemplateAttribute(Struct):
         else:
             return NotImplemented
 
+    def __ne__(self, other):
+        if isinstance(other, TemplateAttribute):
+            return not (self == other)
+        else:
+            return NotImplemented
+
 
 class CommonTemplateAttribute(TemplateAttribute):