tests/test-default-push

merge: introduce tool.check parameter

tool.check is a list of check options, and can be used in place of
tool.checkchanged and tool.checkconflicts:

Equivalences:
tool.checkchanged = yes
tool.checkconflicts = no
tool.check = changed

tool.checkchanged = no
tool.checkconflicts = yes
tool.check = conflicts

tool.checkchanged = yes
tool.checkconflicts = yes
tool.check = changed, conflicts

Add _toollist() wrapper for ui.configlist() to implement this consistently.

checkchanged and checkconflicts are still supported, but check is
preferred for implementing new check options.

#!/bin/sh

hg init a
echo a > a/a
hg --cwd a ci -Ama

hg clone a c

hg clone a b
echo b >> b/a
hg --cwd b ci -mb

echo % push should push to default when default-push not set
hg --cwd b push | sed 's/pushing to.*/pushing/'

echo % push should push to default-push when set
echo 'default-push = ../c' >> b/.hg/hgrc
hg --cwd b push | sed 's/pushing to.*/pushing/'