Add a -t <test-branch-prefix> argument to git-merge-forward.sh and
git-push-all.sh, which makes these scripts create, merge forward, and
push test branches.
Add a -r <remote-name> argument to git-push-all.sh, so the script can
push test branches to a personal remote.
Closes ticket 31314.
Set the env vars:
* TOR_MASTER_NAME to override the tor master branch name, and
* TOR_WKT_NAME to override the worktree path
Fixes bug 30841; bugfix on 0.4.0.1-alpha.