While we work on converging pyro.distributions and torch.distributions, we will need a compatibility layer so that torch.distributions can be used inside Pyro. Ideally this layer will become thinner as we move functionality upstream. As torch.distributions matures, we will remove Pyro's older scipy-based implementations.

• Wrap torch.distributions.Normal for use in Pyro #607 Normal
• Wrap torch.distributions.Gamma, Beta #630 Gamma
• Wrap torch.distributions.Gamma, Beta #630 Beta
• Wrap torch.distributions.Gamma, Beta #630 Dirichlet
• Wrap torch.distributions.exponential for use in Pyro #643 Exponential
• Refactor TorchDistribution and wrap torch.distributions.Bernoulli #645 Bernoulli
• Wrap torch Categorical and OneHotCategorical #649 Categorical
• Wrap torch Categorical and OneHotCategorical #649 OneHotCategorical
• Cauchy
• Uniform
• Multinomial
• HalfCauchy
• Poisson
• LogNormal
• Binomial
• Laplace
• Chi2
• MultivariateNormal
• Delta