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.

#!/bin/sh
. $TESTDIR/testlib/pythonpath.sh

# This file holds logic that is used in many tests.
# It can be called in a test like this:
#  $ . "$TESTDIR/testlib/topic_setup.sh"

# Enable obsolete markers and enable extensions
cat >> $HGRCPATH << EOF
[experimental]
evolution=createmarkers,exchange

[extensions]
rebase=
topic=
EOF