[Feature requests] Some improvements.

[baiomys]

Hi.

First of all thanks for simple and efficient tool!

Possible improvements:

1. Seed should be initially random for new session, but locked until dice button is pressed. Then locked again and so on.
2. Button which switches portrait <=> landscape is excellent but not enough. There should be "mul2" and "div2" buttons to quickly switch from preview to render mode without using complex mode presets. Or you can just add configurable drop-down list for resolutions.
3. imgedit mode lacks negative prompt

Thanks!