This commit consists of:
1) Add session management to netconf
2) Modularize the rpc call
3) Improve the error handling
4) Small bug fixes

Change-Id: I023edb76e3743b633ac87be4967d656e09e2b970
diff --git a/netconf/nc_rpc/base/close_session.py b/netconf/nc_rpc/base/close_session.py
new file mode 100644
index 0000000..43babb8
--- /dev/null
+++ b/netconf/nc_rpc/base/close_session.py
@@ -0,0 +1,45 @@
+#!/usr/bin/env python
+#
+# Copyright 2016 the original author or authors.
+#
+# 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 lxml import etree
+import structlog
+from netconf.nc_rpc.rpc import Rpc
+import netconf.nc_common.error as ncerror
+
+log = structlog.get_logger()
+
+class CloseSession(Rpc):
+
+    def __init__(self, rpc_request, rpc_method, session):
+        super(CloseSession, self).__init__(rpc_request, rpc_method, session)
+        self._validate_parameters()
+
+    def execute(self):
+        log.info('close-session-request', session=self.session.session_id)
+        if self.rpc_response.is_error:
+            return self.rpc_response
+
+        self.rpc_response.node = etree.Element("ok")
+        return self.rpc_response
+
+
+    def _validate_parameters(self):
+        for child in self.rpc_method.getchildren():
+            # There cannot be parameters to a close session request
+            self.rpc_response.is_error = True
+            self.rpc_response.node = ncerror.BadMsg(self.rpc_request)
+            return
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