Create local ui object per repository, so .hg/hgrc don't get mixed.
This is needed for hooks, but may be important for other settings, too.
Fixes
issue113, also integrated push-hook-lock.sh as a test case for this.
adding foo
pushing to ../2
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files