DOC/CI: include api docs on travis
Continued in #12002

---

Closes #6100
Closes #3800

Just to check how this takes on travis

might simply want to create a doc-build (e.g. this issue https://github.com/pydata/pandas/issues/3800)
 @jreback yes, I know, but I was first just experimenting a bit to get it working (not very familiar with travis/bash syntax details). Once I have something working the idea was indeed to put it in a separate travis build.

The problem I have now, is that for some reason `make.py` does not output its progress to the standard output of travis (which is the case if you run it locally in a terminal). And then, because of this, travis thinks nothing is happening anymore and aborts the build .. 
Do you know a solution for this?
 http://docs.travis-ci.com/user/build-timeouts/

might work
 is make.py writing to stderr? then could just redirect

maybe it's buffering?
 https://coderwall.com/p/wws2uq/have-travis-ci-test-your-sphinx-docs

?
 https://github.com/Syntaf/travis-sphinx
 `make.py` calls `sphinx-build`, which AFAIU outputs to both stdout as stderr? And also, I would think travis outputs both stdout as stderr in the logs? But it is not really clear to me how it is specified the output of the doc build is logged in a file that is then later shown, and why for tests it is outputted directly.

The `travis_wait` is probably not a solution, as this just raises the timeout from 10 to 20 minutes, but I think the doc build will even take longer.
 aha, hadn't notices that there is also a separate `run_build_docs.sh` script next to `build_docs.sh`, and that is of course capturing that output ..
 @jreback With the last commit the full docs build OK, although it took 37 minutes. So I put it in a separate travis build, and include the full api docs (there is still a temporary commit to let the others fail).

Can you have a look at the travis ci changes? (it also included somes hacks to numpydoc to prevent some warnings, they are not very nice hacks, but the warnings had to be eliminated to get it running on travis (otherwise the log was too big ..)).
 @jorisvandenbossche all looks cool to me then. I know the doc-build takes a while but so what its in the  lower section.

note - the builds run in the order that they are defined in the top section (no matter if they are in th ebottom section or not). So you prob want to have the doc-build run last? (I think you have it that way). That way other workers can finish the other jobs. we can have 5 simultaneously i think.
 The problem with this approach is that the time it takes to build on Travis seems rather variable (maybe depending on its load?). In any case, sometimes it succeeded to finish it in ca 45 min, but other times it goes up to 50min and then travis aborts it. 
But now trying if parallel build speeds it up
 @jorisvandenbossche closing, but reopen if updating

in theory this looks like a great idea....but yeh it takes quite some time to build the API docs
 Continued in #12002 
