GUI -- Added mechanism to test device view.
Themed device view.

Change-Id: I471ec56b94c927d834f8067d06efce33ddfa4596
diff --git a/web/gui/src/main/webapp/app/onos.css b/web/gui/src/main/webapp/app/onos.css
index 0449853..40a5c03 100644
--- a/web/gui/src/main/webapp/app/onos.css
+++ b/web/gui/src/main/webapp/app/onos.css
@@ -50,6 +50,9 @@
     height: 100%;
 }
 
-#view h2 {
+.light #view h2 {
     color: #800;
 }
+.dark #view h2 {
+    color: #d88;
+}