fixed issues with artists

[clayton-ho]

Changes:

• Fixed an issue where if multiple datasets had the same name, only the most recent would be deleted when loading a new dataset, causing old datasets to pile up. Duplicate datasets now have a number appended to their name based on how many duplicated there are (e.g. "duplicate_dataset (3)").
• Fixed an issue with the naming of datasets where datasets were being named by their legend instead of their label.