update README.md

Author: Scott J. Miles

README.md

@@ -1,4 +1,8 @@
 core-action-icons
 =================
 
-See //polymer.github.io/core-action-icons
+This is a _resource_ component which contains image assets for the default core icon set.
+
+While HTML, JS, and CSS can be combined for production deployments by tools like Vulcanizer, some assets are easier to deliver as is. 
+
+Projects using the default core icon set should include this componentin deployments verbatim.