Dub Editor 1.1.2a
The tool is now capable of handling packs of clips and can import and export clips in and out of the tool. And most importanly it can launch the game with a pack of clips.
If you are going to make your clip packs by hand, you must create a zip that has StreamingAssets at the top of the directory structure and StreamingAssets/VideoClips and StreamAssets/Subtitles with your custom content. The tool can create properly structured packs without the extra effort though.
UPDATE: Fixed a bug that occurs in new Windows installs.