OAStackViewDistributionFillProportionally implemented

[bartvandendriessche]

Did a quick draft implementation for the FillProportionally distribution.

Also updated the Example project so that:

• Distribution strategies can be switched
• Buttons have different intrinsicContentSize

[nsomar]

Hello, super cool addition 👍
Are you planning on adding some test coverage for these distribution? If not, then I might add coverage and merge it over the weekend.

[bartvandendriessche]

Heya, not sure if I'll have time over the weekend to add tests.

If I do, I'll try to add some tests. If you've already added them by then, I might try to fill in some other feature, so by all means, don't wait for me :)

[bartvandendriessche]

Quick side note, the tests check that the proportional view is within a range of 1 point of the 'calculated reference value', because AutoLayout tries prevent misaligned views (i.e. it will round).

[nsomar]

Wonderfull addition 👍 merging right away :)