Updated exportdb to add migrate library feature

Added

• --migrate-photos-library option added to osxphotos exportdb to migrate the export database from one Photos library to another. This is useful when moving to a new computer but maintaining the existing osxphotos export. Thanks to @swduncan for the idea. (#990)

Fixed

• Fixed a bug in osxphotos export --cleanup to handle files which could not be deleted. Thanks to @oPromessa for finding this and suggesting the fix. (#987)

Internal

• Fixed a bug that caused rich_echo() to not display rich text if --verbose wasn't specified.

Contributors

• @RhetTbull for code changes.
• @promessa who found the cleanup bug and suggested a code fix.
• @swduncan who suggested the library migrate use case.