Fixes to loading

This fixes:
- If app height is greater than 400px the loading fade looks pretty jerky, so I wait for everything to be ready before expanding the height above 400px.
- Added `created` and `domReady` steps to the progress bar, and made step weight and order dynamic.
- Moved `ceciappattached` event out of `this.async` and now we can use `domReady` which is the same thing as attached inside an async, exactly what I have been looking for.
- `polymer-ready` is fired too soon when first run on a clear cache, which mean it was run before I setup the load event thus missing it and choking. `domReady` is much more reliable for this, and now when things fail we just don't get a progress bar instead of choking.