Add an upper threshold for size to `pcv.fill`

[HaleySchuhl]

Is your feature request related to a problem? Please describe. There are some applications where the goal is to remove large objects and small objects, and only keep the middle-sized objects. Thanks to @kmurphy61 for this feature request.

Describe the solution you'd like What I've done before is apply pcv.fill once initially to remove small unwanted things and store to a mask we can call medium_large, and then make another mask with pcv.fill that removes medium-sized with a larger size parameter so all that remains are things that are unwanted because they are too large . Finally using pcv.image_subtract to keep only medium sized things by doing keep = medium_large - large . Perhaps this is functionality that we could apply in the background only when an upper thresh is specified so that it's not any slower under "normal" applications?

[nfahlgren]

What if we made a new function that functionally overlaps with pcv.fill but has the upper size threshold as you proposed, but we place it/name it in a clearer way like pcv.filters.obj_size?

We could potentially deprecate pcv.fill then at a later date/version.

[HaleySchuhl]

I like that plan. Plus just reminded me to actually open a PR for pcv.filters.solidity

[HaleySchuhl]

Closed with #1555