Seed in batches not incremented

[Photosounder]

When you do a batch in txt2img the seed is not incremented. It's inconvenient because you lose track of the original seed in the output files since it shows the first seed rather than the correct seed.

Since it's an easy fix I did it myself on my own fork, although it doesn't affect the Seed: field inside the file, please let me know if you know how to change this, although it's a small detail. Not doing a PR because I'm just changing a bunch of things on my side to my liking. Feel free to copy anything you want from my fork.

My fix is in those lines: Photosounder@11d7252#diff-f08ab7fa504908b1f32ceef9417d6402ae07cc63213d164fe2f3f0d6f1e5b825R427-R430 and Photosounder@11d7252#diff-f08ab7fa504908b1f32ceef9417d6402ae07cc63213d164fe2f3f0d6f1e5b825R513