Added the velocity header template.
diff --git a/tools/dev/header.txt b/tools/dev/header.txt
new file mode 100644
@@ -0,0 +1,13 @@
+Copyright $today.year Open Networking Laboratory
+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
+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.
\ No newline at end of file