Enhancements
- 543 Added `ProvenanceTensor` for torch backend
- 543 Added `Constant` funsor
- 549 Added `funsor.recipes.forward_fiter_backward_rsample()`
- 553 Added a `Precondition` interpretation for Gaussians, plus `funsor.recipes.forward_fiter_backward_precondition()`
- 572 Support Funsors in `pprint.pprint()` and pdb
Breaking changes
- 568 Switch to `sqrt(precision)` representation for `Gaussian`