Optimize Google Maps Store Locator

Hey javascript programmers: I need some optimization done to a Google Maps Store Locator. Here's what I'm using: [login to view URL] You can download it here: [login to view URL] Just make the changes and send it back to me. You won't need to integrate it or anything, just use the Panel example. There are 2 things that it needs: 1. A loading indicator. This will be used on mobile devices so we need something to show the user that the map is still adding the markers. It doesn't need to be styled. 2. Add Marker Cluster. See here: [login to view URL] Any other optimizations would be great as well, let me know your thoughts. We're using a .csv file just like the example.