add support for streaming clone. existing clone code uses pull to get changes from remote repo. is very slow, uses lots of memory and cpu. new clone code has server write file data straight to client, client writes file data straight to disk. memory and cpu used are very low, clone is much faster over lan. new client can still clone with pull, can still clone from older servers. new server can still serve older clients.

#!/bin/sh

hg init test
cd test
echo foo > foo
hg add foo
hg commit -d '0 0' -m commit-1
echo foo >> foo
hg commit -d '1 4444444' -m commit-3
hg commit -d '1	15.1' -m commit-4
hg commit -d 'foo bar' -m commit-5
hg commit -d ' 1 4444' -m commit-6
hg commit -d '111111111111 0' -m commit-7

echo bar > bar
hg add bar
rm bar
hg commit -d "1000000 0" -m commit-8 2>&1 | sed -e "s:/.*\(/test/.*\):...\1:"
exit 0