[Suggestion] half UV guide lines

[Cub0use]

When making optimized UVs manually, it would be useful to have a tool to toggle lines going through the middle of the UV with the accent color, to visualize how to fit geometry UVs (to halve or make the texture size a quarter of what is was)

maybe have lines going through the nearest smaller power-of-two (4, 8, 16, 32, 64, 128 etc) resolution, and not half of the current texture actually (because this loaded texture is not necessarily a power-of-two)