evolve: add an `--update` flag to `hg evolve` command This patch adds a new `--update` flag which defaults to True. The update flag updates the working directory to the head of evolved revisions after `hg evolve` command. This flag can be used to not update your working directory after `hg evolve` which has been one of the biggest feature request from fig team at Google. To not update your working directory, the user can do `hg evolve --no-update`. If the working directory get obsoleted by evolve command, it will update to the successor. This patch also adds some basic tests for the flag introduced.

. $TESTDIR/testlib/pythonpath.sh

mkcommit() {
   echo "$1" > "$1"
   hg add "$1"
   hg ci -m "$1"
}

getid() {
   hg log --hidden --template '{node}\n' --rev "$1"
}

cat >> $HGRCPATH <<EOF
[alias]
debugobsolete=debugobsolete -d '0 0'
EOF