Add ui method to set --ssh/--remotecmd, use it in init/clone/pull/push/in/out.
The only user visible change is that 'hg init' now accepts this options, too.
#!/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/'