Mask exclusion/integration

[Jonathanese]

I was looking at the source to add a simple version of this feature myself.

Basically, when refining my tagging, it kinda sucks having to sort through mask files at the same time.

Level 1. What I was trying to do was just have the image loader ignore files with "_masklabel.png". This could be thrown into a checkmark, maybe using a list of common mask names.

Level 2. Be able to filter out an arbitrary chunk of text in the filenames.

Level 3. Incorporate the mask in how the image is displayed.

Level 4. Be able to generate masks.

Level 5. Be able to edit masks.

A lot of this is doable in OneTrainer. But OneTrainer is pretty minimal in terms of tagging.

[jhc13]

You can put something like "not masklabel" in the Filter Images box to filter out those images.