Update our pybind11 wrappers as needed to use pybind11's native Eigen support. This is necessary in order to upgrade to Eigen 3.3.
- Build ndarray without EigenView support and with native pybind11 Eigen support. The latter is not necessary but avoids the need to change all our wrappers that wrap code that uses Eigen to explicitly import pybind11/eigen.h
- Update code and tests and needed. For example geom has one failing test because pybind11's Eigen wrappers are more lenient than ndarray, so it is now possible to construct an lsst.geom.Extent2I from an lsst.geom.Extent2D.