Clean up warnings/errors in TRAVIS-CI build

[esilvia]

Clean up warnings/errors in TRAVIS-CI build

[hobu]

We can ignore most of the LaTeX warnings. It's an unsatisfactory rabbit hole to follow. If there are more issues like #44, let's open them separately.

[esilvia]

titlesec bug appears to have been fixed in version 2.10.2: https://tex.stackexchange.com/questions/299969/titlesec-loss-of-section-numbering-with-the-new-update-2016-03-15/300259#300259

I can't figure out where titlesec.sty is packaged, though.

[esilvia]

Ah, it's part of the ubuntu Xenial package: https://bugs.launchpad.net/ubuntu/+source/texlive-extra/+bug/1574052/comments/10

[esilvia]

@hobu Do you know how to retrieve an updated version of titlesec.sty? Is that something we'd do in travis.yml or maybe Docker?

[esilvia]

Not only that, I've learned that some of the LaTeX warnings are emitted by design, forcing a second pass after table widths (for example) are calculated in the first pass, so fixing them would be fruitless.