Address all four review concerns on PR #31:
1. Fix missed bare fmt.Println() in VerifySnapshotWithOptions (line 620)
2. Replace all direct fmt.Fprintf(v.Stdout,...) / fmt.Fprintln(v.Stdout,...) /
fmt.Fscanln(v.Stdin,...) calls with helper methods: printfStdout(),
printlnStdout(), printfStderr(), scanStdin()
3. Route progress bar and stderr output through v.Stderr instead of os.Stderr
in restore.go (concern #4: v.Stderr now actually used)
4. Rename exported Outputf to unexported printfStdout (YAGNI: only helpers
actually used are created)
9879668c31