Enhancing STC and scenarios.

Change-Id: I57a4d25b7fb726a1242073055474ff5c7c3c1087
diff --git a/utils/stc/src/main/java/org/onlab/stc/Group.java b/utils/stc/src/main/java/org/onlab/stc/Group.java
index a094828..0281c36 100644
--- a/utils/stc/src/main/java/org/onlab/stc/Group.java
+++ b/utils/stc/src/main/java/org/onlab/stc/Group.java
@@ -31,11 +31,13 @@
      * Creates a new test step.
      *
      * @param name    group name
-     * @param command group default command
+     * @param command default command
+     * @param env     default path to file to be sourced into the environment
+     * @param cwd     default path to current working directory for the step
      * @param group   optional group to which this step belongs
      */
-    public Group(String name, String command, Group group) {
-        super(name, command, group);
+    public Group(String name, String command, String env, String cwd, Group group) {
+        super(name, command, env, cwd, group);
     }
 
     /**