Make Strip waste less waste by being smarter about remainder with at_most

[e00E]

Consider a Strip defined with the following sizes:

1. Size::remainder().at_most(100)
2. Size::remainder()

Let's say the available size is 1000. In this case Strip will end up assigning space like this:

1. 100
2. 500

This leaves 400 wasted space. Strip takes up the extra 400 but it is not assigned to any cell. Instead I would like Strip to assign space like this:

1. 100
2. 900

This leaves 0 wasted space.

More generally, I would like the remainder calculation to take the upper limits into account and distribute the gained space to the other remainders.

I've looked at the implementation of Strip. I can make this change if you (maintainer) tell me you want it.

[emilk]

Sounds good!