NEW: Delete custom presets and datasets

Two new features are included in this update: custom presets can be deleted and uploaded datasets can be deleted. Both of these features are extremely useful for anyone who has a large number of assets and wishes to organize them as well as remove older assets from their collections.

To delete a preset, go to the Playground page and click the "Presets" dropdown. You will see a "Delete" button next to each custom preset, grouped under "My Presets".

To delete a dataset, go to the Datasets page and click the "Delete" button next to the dataset.