Exoplanet

++++++++++++++++++

- Adds support for fitting circular orbits with duration
- Adds a ``bls_estimator`` for transit search using Astropy's ``BoxLeastSquares``

++++++++++++++++++

- Improves infrastructure for generating documentation
- Adds an ``EclipsingBinaryLightCurve`` for building binary star models
- Adds ``DensityDist`` implementation for celerite GP likelihoods

++++++++++++++++++

- Makes ``rebound`` an optional dependency

++++++++++++++++++

- Adds ``ConditionalMeanOp`` and ``DotLOp`` for scalable conditional mean calculation
and prior sampling with celerite
- Adds developer documentation
- Moves documentation to a separate repository

++++++++++++++++++

- Adds ``TTVOrbit`` tutorial
- Switches tutorials to `lightkurve <https://docs.lightkurve.org>`_ for data access
- Improves packaging and code style features
- Fixes bugs and improves interface to ``TTVOrbit``

++++++++++++++++++

- Adds a new interface for tuning dense mass matrices with less overhead
- Adds support for photodynamics using `rebound <https://rebound.rtfd.io>`_
- Adds a new interface for assigning units to Theano variables
- Adds new physically-motivated distributions for impact parameter and
eccentricity
- Improves test coverage
- Fixes bug in diagonal elements of the ``IntegratedTerm`` model
- Fixes bug in indexing for ``TTVOrbit`` models with large TTVs