TST: wrong indent in multiarray tests
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]
BUG: fix #3017 Inconsistency in indexing 0-d arrays with Ellipsis.
TST: added test for issue #3017.

Also changed style to please numpy developers.
BUG: ufunc_at needs_api requires init to 0

as reported by valgrind...
DOC: adding 'Returns' section to `empty` function

This matches the format of related functions like `empty_like` and `zeros`.
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
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
WIP: bug fixes and field oder access change
WIP,TST: Fixup python3 tests
WIP: fix field order; And MapIterNext iteration end
WIP,TST,DOC: tiny fix

maybe triggers Travis too...
WIP: Move Ellipsis setting check and clear warnings