Adding support for the CreateKeyPair operation

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

kmip/core/utils.py

@@ -107,3 +107,16 @@ class BytearrayStream(io.RawIOBase):
 
     def length(self):
         return len(self.buffer)
+
+    def __str__(self):
+        sbuffer = bytes(self.buffer[0:])
+        return str(hexlify(sbuffer))
+
+    def __len__(self):
+        return len(self.buffer)
+
+    def __eq__(self, other):
+        if isinstance(other, BytearrayStream):
+            return (self.buffer == other.buffer)
+        else:
+            return NotImplemented