v7.0.0

What's Changed

• Improve documentation by @danielward27 in #57
• Imrpove documentation structure by @danielward27 in #58
• Use math instead of jnp in TanhLinearTails init by @danielward27 in #59
• Multiple ndim by @danielward27 in #61

#61 introduces important (and breaking) changes:

1. Distributions and bijections now have shapes, rather than assuming everything is a vector with shape (dim, ). Distributions and bijections must define the attributes shape and cond_shape (see Distribution and Bijection).
2. distribution.sample() now has a sample_shape: Tuple[int] argument, replacing n: int. Providing sample_shape=(n,) is equivalent to the previous n=n.
3. Transformers have been removed, instead Bijection types can be used directly as transformers. i.e. Affine() or RationalQuadraticSpline(**args) should be used instead of AffineTransformer(), RationalQuadraticSplineTransformer(**args).
4. RationalQuadraticSpline arguments renamed to knots and interval, rather than k and B
5. Rename ScannableChain to Scan.
6. Better documentation.
7. Bumps version to 7.0.0

Full Changelog: v6.1.0...v7.0.0