Adding commands for managing layouts.

Adding support for wiping out regions and layouts.
Refactored UI layout manager to allow public knowledge of default layout id.
Enhanced test topo for layout hierarchy.

Change-Id: I254fd494175e753f542f12a664618c1a83f72127
diff --git a/tools/test/topos/regions-topo-2 b/tools/test/topos/regions-topo-2
index bf380ef..5a18c91 100755
--- a/tools/test/topos/regions-topo-2
+++ b/tools/test/topos/regions-topo-2
@@ -1,4 +1,5 @@
 #!/bin/bash
+# Test topology
 
 host=${1:-127.0.0.1}
 
@@ -6,8 +7,6 @@
 onos ${host} wipe-out please
 onos ${host} null-simulation start custom
 
-sleep 1
-
 onos ${host} <<-EOF
 
 null-create-device switch s1 10 0 0
@@ -35,8 +34,6 @@
 
 EOF
 
-
-
 onos ${host} <<-EOF
 
 region-add r1 Region1 METRO ${host}
@@ -58,4 +55,10 @@
     of:0000000000000009
 
 regions
+
+layout-add l1 r1
+layout-add l2 r2
+layout-add l3 r3 l2
+
+layouts
 EOF
\ No newline at end of file