[ONOS-4650][ONOS-4726][ONOS-4727] [ONOS-4728]Implement must parser + when parser + feature + if-feature + revision defect fix

Change-Id: I0a3aee6c1c6b72ef7da7f7f565fd0f149fe3fd42
diff --git a/utils/yangutils/datamodel/src/main/java/org/onosproject/yangutils/datamodel/ResolvableType.java b/utils/yangutils/datamodel/src/main/java/org/onosproject/yangutils/datamodel/ResolvableType.java
index 9521f41..058e947 100644
--- a/utils/yangutils/datamodel/src/main/java/org/onosproject/yangutils/datamodel/ResolvableType.java
+++ b/utils/yangutils/datamodel/src/main/java/org/onosproject/yangutils/datamodel/ResolvableType.java
@@ -29,5 +29,10 @@
     /**
      * Identifies the uses.
      */
-    YANG_USES
+    YANG_USES,
+
+    /**
+     * Identifies the if-feature.
+     */
+    YANG_IF_FEATURE
 }