DEP: non-integer scalar python sequence repeat

This starts deprecation for code such as
np.float_(3.4) * [1, 2]
which should only work for integer objects. It may be possible
to just return NotImplemented since at least python sequences
implement their multiply themself through __index__.

Further action is only needed for PyArray_PyIntAsIntp, so this
is part of a larger deprecation now.

Closes gh-4036
DOC: Add an example of casting array type and byte order using astype.
DOC: Spelling correction for numpy.diag see also
Merge pull request #4037 from migueldvb/docs

Example to convert the type of an array using the astype method and minor typo fix
Spelling: loose -> lose
spelling: AC -> AD in years

(could also use BCE and CE to be more politically correct)
BUG: ma.compressed() function returns masked array

When a masked array with nomask was passed to ma.compressed()
function, the result was the original masked array instead of
an ndarray.

Closes gh-4026.
Merge pull request #4039 from abalkin/issue-4026

BUG: ma.compressed() function returns masked array
Merge pull request #4046 from chatcannon/speling

Spelling & notation corrections
Merge pull request #4038 from seberg/issue-4036

DEP: non-integer scalar python sequence repeat