Travis CI timeouts for MacPorts builds

[Ralph Seichter]

* Mojca Miklavec:

> What we need is:
> - a list of recipes to set up images for a bunch of different macOS
> versions (as far back into history as possible)
> - a recipe for how to fire up a VM, do something basic (port install
> foo) and trash the result

Looking at the Travis CI config and the raw Travis logs, I don't see
much. Are more detailed log files available? The magic seems to happen
in the code hosted in mpbot-github.

-Ralph