-->Download it here<--
The script saves each top layer in a file to a separate file and can create a batch file that will render all the files as png sequences.
The options:

Save automatic batch file. If this is unchecked the other options won't matter.
Put each render in it's own folder. If unchecked all renders will be put in one folder. Some compositors, like After Effects, can still import them as separate sequences.
Number layers in descending order. All layers will be saved with a number in front so you know what goes where. With this checked it will start numbering layers from the top.
Directory of Anime Studio. Needed for the batch file.
Delete files after render. This will delete the separate .anme files that were created, NOT the original file or the rendered images.
After you've run the script just double click the batch file and the rendering will start.

You won't get any progress, just the time when a new file has started rendering. This doesn't bother me much, I'll just start the render and start working on the next scene while it renders in the background.
Some notes:
-This will only work in Anime Studio Pro 8 on Windows.
-When you run the script it will save the currently open file so don't run it if you don't want to save it like it is right then and there.
-Layers with "_null" anywhere in the name will be skipped. This is pretty specific to my own workflow but it might be good to know.
-It could save to other formats than png but you'd have to edit the script file and replace any occurences of png with the format you want. Since I only use png I haven't bothered making it an option.