They're putting up the 3rd tower crane this morning. The building is almost at street level on the east side of the block.
Also if you use the camera link below you can see that they've turned on the lights at the Whitley apartment tower across the street from the JW Marriott. Hyatt Place also has turned on its sign lights.
And yes, that is a spider on the camera lens. Apparently spiders have a thing for camera lenses on tower cams. I also saw one on Fox7's tower cam.
http://oxblue.com/open/tournee/jwmarriottaustin
Screenshot from this morning at 11:52 am.