ENH: Initial skeleton implementation of node slicing
ENH: Initial skeleton implementation of node slicing

Slice node makes it possible to select a subset of plates from a node.
The slicing works similarly as basic slicing in NumPy: it supports
integers (positive or negative), Ellipsis (...), newaxis (None) and
slices (start:stop:step).

jluttine/bayespy,bayespy/bayespy,fivejjs/bayespy,SalemAmeen/bayespy