Dynesty

Changed
- Added two new slice sampling options (`'rslice'` and `'hslice'`).

- Changed internals to allow user to access quantities during dynamic batch
allocation. **WARNING: Breaks some aspects of backwards compatibility
for advanced users utilizing generators.**

- Simplified parallelism options.

- Fixed a singular decomposition bug that occasionally appeared during runtime.

- Small plotting/utility improvements.

Changed
- Fixed additional Python 2/3 compatibility bugs.

- Added the ability to pass user-specified custom print functions.

- Added importance reweighting.

- Small improvements to plotting utilities.

- Small changes to improve user outputs and basic functionality.

Changed
- Fixed `map` bugs that broke compatibility between Python 2 and 3.

- Fixed a bug where the sampler could break during the first update from the
unit cube when using a `pool`.

Changed
- Introduced a function wrapper for `prior_transform` and `loglikelihood`
functions to allow users to pass `args` and `kwargs`.

- Fixed a small bug that could cause bounding ellipsoids to fail.

- Introduced a stability fix to the default
`~dynesty.dynamicsampler.weight_function` when computing evidence-based
weights.

Changed
- Initial beta release.