At least some of the build problems here were pre-existing; master fails in Travis too if I kick it.

Debugging that has at least reminded me of the issue with Eigen 3.2: there is support for equivalent functionality with Eigen 3.3 via a different interface, and I just didn't want to remove the old one completely without some deprecation period, so it's been gated in CMake. Over on #79 I'm now removing it entirely, along with a bunch of other cruft that's unused by LSST or (AFAIK) any other ndarray users. Once that's done I'll either try to cherry-pick some of your commits or ask you to rebase and clean up your branch, depending on how much time I have.

Closing in favor of #80, which is my rebased version of this branch without the need to pin Eigen.