Update the server session to use the auth plugin framework

This change updates how the server session handles message
processing, adding support for the new authentication plugin
framework. Session unit tests have been updated to account for
this change.

kmip/core/exceptions.py

@@ -38,6 +38,25 @@ class KmipError(Exception):
         self.status = status
         self.reason = reason
 
+    def __eq__(self, other):
+        if isinstance(other, KmipError):
+            if str(self) != str(other):
+                return False
+            elif self.status != other.status:
+                return False
+            elif self.reason != other.reason:
+                return False
+            else:
+                return True
+        else:
+            return NotImplemented
+
+    def __ne__(self, other):
+        if isinstance(other, KmipError):
+            return self == other
+        else:
+            return NotImplemented
+
 
 class CryptographicFailure(KmipError):
     """