Make batching easier

[edgeworn]

This PR makes a few changes to make it easier to batch a large number of uploads

• Add a spectrogram_only flag, to allow the user to generate and look through all of their spectrograms at once instead of needing to do them one by one as they are generated during the upload process
• Replaces forbidden characters in base_name to prevent uploads from failing
• Prints errors and continues to the next item instead of aborting entirely

Let me know if there's anything you'd like me to change

[edgeworn]

Thanks for the comments! I probably won't have time until the weekend but I'll address them soon

[edgeworn]

updated, thank you! i'll make a follow up to add a generate_spectrograms command

[DevYukine]

This fixes #4