Switch cat command to use walk code.
The old syntax of "hg cat FILE REV" is now obsolete.
Use "hg cat -r REV FILE" instead, as for all other commands.
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 1 changesets, 1 total revisions