History of Swarm::layout 2 changes

In crates/backdrop/src/swarm.rs, lines 88–112 on v0.7.0. Every change that wrote or deleted one of these lines, or deleted a line from between them. Exact, because each line keeps its identity across edits; edits elsewhere in the file are not here. Also: oxy log -L 88,112:crates/backdrop/src/swarm.rs.