evolve: skip unstable changesets with multiple successorssets We were previously crashing when encountering them, but we want to be able to solve the other solvable troubles instead of stopping right there.

evolve: allow multiple --rev argument This is standard behavior for Mercurial commands.

test-evolve: fix tests failing on some platform We change from echo to printf to print newlines so that evolve's tests work cross-platforms.

evolve: prevent using --rev and --any together Before this patch it was possible to use evolve --rev --any and it meant evolve --rev. This patch throws an error when using evolve --rev --any.