evolve: unify revision handling and rework error message This changesets do a massive refactoring of the way evolve select changesets to be evolve. We now use a two stages approach: 1) read command line argument and produce a list of revision to evolve. 2) evolve all these revisions. This allow a much cleaner, robust and extensible code. In the process the error message issued when there is nothing to evolve have been updated to informs about other troubles in the repository and point at useful option to solve them. The 'update' case is handled independently at the start of the function.

evolve: move the 'update' if '.' is obsolete earlier A big refactoring of the computation of the revision to evolve is coming. This case won't be handled by it, so we extract it earlier.

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.

evolve: add selector for trouble types This patch adds command line flags to select the kind of troubles to solve. Before this patch evolve was solving any kind of troubled. With this patch evolve --all and evolve --rev can be configured to only solve only some type of troubles (divergent, bumped or unstable). To give this choice to the user we add three new command line flags to the evolve command: --bumped, --divergent and --unstable.