evolve: abort when trying to move a node on top of itself This provides a clearer error message when evolve misstakenly tries to move a changeset on top of itself. Before we got an abort with a cryptic message about trying to rebase a merge changeset. A proper fix to make sure that evolve never tries to move a node on top of itself will come in later patches.

run-tests: add executable bit

rewrite: use cmdutil.logmessage instead of ad-hoc methods The logic for handling the --message and --logfile options is already in core hg in the cmdutil.logmessage function. This patch removes this duplicate logic from Evolve and just calls the core function.

fold: enable --date and --user options Like all other commit-creating commits, `hg fold` should also have these options enabled. This also allows getting consistent hashes during tests involving fold.