BUG: fix #3017 Inconsistency in indexing 0-d arrays with Ellipsis.
BLD: fix Bento build.

Issue was introduced with PR-3524, the ufunc override stuff.
BLD: add new test extensions (rational, struct_ufunc, operand_flag) to Bento build.
DOC: [bento] document that adding optional GCC performance improvements is TODO

[ci skip]
TST: added test for issue #3017.

Also changed style to please numpy developers.
TST: wrong indent in multiarray tests
Merge pull request #3781 from seberg/test_multiarray-indent

TST: wrong indent in multiarray tests
Merge pull request #3766 from rgommers/fix-bento-build

Fix bento build
BUG: INCREF before DECREF when copying object arrays.

Only the change in dtype_transfer actually seems to be
related to the simple np.copyto(a, a) bug, when a is a scalar
object array.
It seemed however safer to me, to generally turn around the
logic, even if it may not be necessary and in one place
requires an extra temporary variable.

Closes gh-3787
Merge pull request #3757 from dimasad/issue-3017-fix

BUG: fix #3017 Inconsistency in indexing 0-d arrays with Ellipsis.
DOC: adding 'Returns' section to `empty` function

This matches the format of related functions like `empty_like` and `zeros`.
BUG: ufunc_at needs_api requires init to 0

as reported by valgrind...
Merge pull request #3795 from seberg/init_ufunc_at_needapi

BUG: ufunc_at needs_api requires init to 0
Merge pull request #3794 from perimosocordiae/patch-1

DOC: adding 'Returns' section to `empty` function docstring
Merge pull request #3788 from seberg/object-copy-refs

BUG: INCREF before DECREF when copying object arrays.
ENH: Attempt to rewrite the index parsing.

Some optimizations still missing.
WIP: Speed improvements by using EXTERNAL_LOOP
WIP,TST: Fix tests to match new behaviour
WIP: use fast_take and fix Deprecations
WIP,TST: Small fixes for the tests