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 -e
umask 027
mkdir test1
cd test1
hg init
touch a b
hg add a b
hg ci -m "added a b" -d "1000000 0"
cd ..
mkdir test2
cd test2
hg init
hg pull ../test1
hg co
chmod +x a
hg ci -m "chmod +x a" -d "1000000 0"
cd ../test1
echo 123 >>a
hg ci -m "a updated" -d "1000000 0"
hg pull ../test2
hg heads
hg history
hg -v co -m
ls -l ../test[12]/a > foo
cut -b 1-10 < foo