tests/test-1102

branch closing: mark closed branches with a 'close' extra

Adds a --close-branch option to commit.
When --close-branch is present the commit will mark the changeset
with close=1 in the changeset extras field.

If a regular changeset is added on top of a closed head the branch
is no longer considered closed, and thus re-opened.

#!/bin/sh

rm -rf a
hg init a
cd a
echo a > a
hg ci -Am0
hg tag t1 # 1
hg tag --remove t1 # 2

hg co 1
hg tag -r0 t1
hg tags