save transitions to individual tracks

Save transitions to the individual track so that when creating a new mix from scratch, a user can import a previously used track with the same transition start/end points, stems, automation, and fx.

As a former Mixmeister Pro user, it made the workflow so easy because I could highlight an entire mix, right-click, and save all of the transitions for each individual track. As a lifelong radio mixshow DJ, our playlists evolve, meaning we found ourselves playing many of the same songs each week. I could create mixes with lighting-fast speed when I was in a time crunch and needed to make a quick mix to play on air while prepping for a concert or club gig in the "real world".