It downloads all referenced assets and scripts for the case and creates a version of it that works completely offline. The GitHub page linked above describes some additional features (e.g., downloading multiple cases at once, or choosing a specific player version) and how to install and use it. This program doesn't have a GUI, so you'll need to invoke it on the command-line. You can pass "--help" to get detailed information on its usage and options.
I should note that this isn't an official tool, and I can't make any guarantees that it'll always work—I only tested it on a handful of cases, where I couldn't find any problems, but it's totally possible that there are some edge cases I missed. If you notice a problem or have a feature request, feel free to tell me either in this thread or by opening an issue in GitHub.
EDIT: I added some additional features since I posted this, such as:
- Passing the "-1" parameter compiles the case into a single HTML file (i.e., no separate asset folder).
- The user scripts by Time Axis can now be integrated into the offline cases by passing the "-u" parameter.
- Sequences are correctly "connected" to each other.
- Photobucket watermarks are automatically removed.
- A bunch of bugs have been fixed, thanks to Time Axis' numerous bug reports.