I made some fixes to address the excessive number of backup files when loading pattern or measurement files that need converting from an older format version.
- Limits the backup to 1 file.
- Eliminates appending the version number from the backup file name and just appends (Backup) to the base name.
- Adds a preference to enable backups when converting files to give user choice whether they want any backups.
- Adds a “My Backups” file path preference to where a user wants to store backups, and creates a default directory “[homepath]/seamly2d/backups” if it does not exist when the app runs.
