Name blueprint storage backups for any apparent map version

[quyxkh]

For instance, blueprint-storage-backup-16.26.dat

The v16 splitter and compression experiments have had me going back and forth trying to find out whether my factory breakage was due to version changes or just not-good-enough designs. blueprint-storage-backup.dat is empty now, I think because I went back in steps to find when things stopped working.