CI / BLD: Various CI Backports
* Pin `blosc` to `1.14.3` (#22429)
* Migrate to CircleCI 2.0 (#21814)
* Pin `openpyxl` to `2.5.5` (#22601)
* Bump `numpy` to `1.9.3` (#22499)
* Fix locale handling (#21739, #22213)
* Upgrade `Cython` to `>=0.28.2` (#21688)