Image tiling

[k034b363]

Is your feature request related to a problem? Please describe.
When choosing parameters for either model fitting or segmentation, it would sometimes be useful to visualize several output options all at once, similarly to visualize.colorspaces.

Describe the solution you'd like
A function that takes as input a list of images (could be rgb, binary masks, grayscale) and row/col dimensions and will plot to screen a tiled composite of the inputs rescaled for size differences.

Describe alternatives you've considered
Alternatives could either be plotting each output image in a series (which is hard to visualize), or stacking output arrays so that Napari might be used to scroll through the stack. I can see advantages to either over a tiled output, but think it's worthwhile as an option.