Ligo.skymap

==================

- Move ``ligo.skymap.eigenframe.EigenFrame`` to
``ligo.skymap.coordinates.EigenFrame``.

- Add a new Astropy coordinate frame ``ligo.skymap.coordinates.DetectorFrame``
to visualize triangulation rings with pairs of detectors.

- Deprecate all functions in ``ligo.skymap.postprocess.detector_frame``.

- Overhaul documentation so that all essential functionality is presented on
the front page.

- Move ``ligo.skymap.command`` to top-level ``ligo.skymap.tool`` module.

- Require version 0.3.2 of the ``reproject`` package because of a regression
that was caused by improper handling of nans in the ``astropy-healpix``
package. See <https://github.com/astropy/astropy-healpix/pull/77>.

==================

- Declare the top-level ``ligo`` module as a namespace package.

- Update common files from Astropy package template.

- Enable Python version check in ``setup.py`` and top-level namespace package.

==================

- When running ``ligo-skymap-stats`` without injections, instead of writing
``nan`` values for irrelevant columns, don't write the columns in the first
place.

- Start process of switching to tqdm for progress bars so that long-running
operations show time estimates.

- In ``ligo-skymap-stats``, disable OpenMP parallelism if running with ``-j``
to avoid creating a huge number of threads on machines with very many
cores.

==================

- Fix ``--condor-submit`` option for ``bayestar-localize-coincs``.

- Add ``--duty-cycle`` option to ``bayestar-realize-coincs``.

- Rename ``ligo-skymap-aggregate-found-injections`` to ``ligo-skymap-stats``
and ``ligo-skymap-plot-found-injections`` to ``ligo-skymap-plot-stats``. The
new ``ligo-skymap-stats`` program can generate summary statistics for
skymaps, with or without injection-finding.

- This is the first version that has been tested and shown to reproduce the
results in the "First Two Years" paper, which is the review benchmark.

==================

- Bring back simulation tools from LALSuite.

- Add ``ligo-skymap-plot-airmass``, a tool for probabilistic airmass charts.

==================

- Adjust CI configuration for uploading to PyPI.