Variant builds in travis-ci

[arekinath]

We should run the build.rb script in travis-ci to generate all the CAP files for the different variants automatically.

[mistial-dev]

Travis-ci.org went commercial shortly after this issue was created, and then went read-only.

@arekinath would you like me to take a look at building under Github Actions?

[arekinath]

@mistial-dev yeah, we should move it over to github actions I guess. I need to move a bunch of my other repos over as well at some point, I was being lazy because I don't often have to change the build settings, so things were mostly still working through most of the drama.