VPP-341: iOAM plugin documentation

Change-Id: I0042ce8b8a70bb709765037c3636be667ad88aa2
Signed-off-by: Shwetha <shwethab@cisco.com>

plugins/ioam-plugin/ioam/dir.dox

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ * 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.
+ */
+/**
+ @dir
+ @brief Inband OAM (iOAM) implementation
+*/