In Terminal.app, run:
cd ~/Library/Application\ Support/Sublime\ Text\ 3/Packages
git clone https://github.com/Xaelias/ST_Plugins.git
Then restart ST3.
No configuration; works as-is. Behavior may not be perfect for everybody, but it has worked well enough for me.
Notes:
- Switching branches WILL erase any unsaved modifications or new files in the buffer--without confirmation. Swapping workspace closes your previous branch's workspace then opens the newly checked-out branch's workspace.
- For the plugin swap workspaces, you must unfocus then refocus the cursor in the editor after checking out a different branch.