Amalgamations (multi-songs that also split into segments)

[mtolly]

First-class support for BTBAM albums, The Mirror/Lie, ITPOE, ACOS, 6DOIT, A Mind Beside Itself, etc.

Obvious way to do this is to have multiple targets for the individual segments. This means targets need the following options:

• Title (instead of just title suffix like we have now)
• Fade-in from (position) to (position)
• Start notes at (position)
• End notes at (position)
• Fade-out from (position) to (position)

Segments (let's not use "parts" or "sections" as those already have meanings) should have the option to automatically renumber practice sections, and they should drop instruments that don't have any notes in that segment.

[mtolly]

Most instruments should be straightforward to "clip" to the appropriate bounds - a tricky one that I realized with Rosetta is when some harmony parts don't have phrases in the bounds. With Rosetta it's just dropping HARM3 which is easy. But in theory you could need to drop H2 and move H3 to H2, or drop H1 and move H2/H3 to H1/H2 (and remove lyric hide commands), or drop 2 of 3 harmonies and make it just solo vox.