simplemerge: flush stdout before writing to stderr.
Besides, stderr is not always unbuffered under win32 (when redirections occur for instance), and it should be flushed too.
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 1 changesets, 1 total revisions