DOC: document broadcastable lam parameter of poisson

closes gh-4526
DOC: fix signature of PyArray_NewShape in C-API docs

closes gh-4579
DOC: remove wrong mention of .gz in np.load

closes gh-312
DOC: fix a couple mistakes in the indexing documentation

closes gh-618
DOC: update numpydoc to tag v0.5
DOC: add full/full_like

closes gh-4805
[ci skip]
Merge pull request #4803 from juliantaylor/doc-updates

Doc updates