add merge command. means same thing as "update -m".
repo.addchangegroup method now returns number of heads modified and added,
so command line can tell whether update or merge needed. this makes
tiny change to ssh wire protocol, but change is backwards compatible.
pull command now returns 0 if no changes to pull.
#!/bin/sh
# No local source
hg clone a b
echo $?
# No remote source
hg clone http://127.0.0.1:3121/a b
echo $?
rm -rf b # work around bug with http clone
# Inaccessible source
mkdir a
chmod 000 a
hg clone a b
echo $?
# Inaccessible destination
mkdir b
cd b
hg init
hg clone . ../a
echo $?
cd ..
chmod 700 a
rm -rf a b
# Source of wrong type
mkfifo a
hg clone a b
echo $?
rm a
# Default destination, same directory
mkdir q
cd q
hg init
cd ..
hg clone q
true