Great addition to customization.

Thanks for this PR, I check it out during the weekend.

@mdflores I reviewed your PR, but there are some problems.

First of all, the name for the two constraints is ambiguous, because inside the alert there are two UIStackViews, one for title and description, and one for the buttons (PMAlertAction).
You named the constraints alertStackViewLeadingConstraint and alertStackViewTrailingConstraint but there is another constraint called alertStackViewHeightConstraint that is a reference to the 2° stack view. Then, try to find a name to disambiguate.

The second point: you implemented this feature, but is interesting to implement the same on the second stack view (alertActionStackView).

Please, integrate this and I can approve your PR.
Thanks

-Paolo

I've expanded on this pull request and addressed your comments @pmusolino #61

Closed in favor of #61