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
WIP: Restore binary compatibility of MapIterObject (hopefully)
WIP,ENH: Already allow boolean scalars for 0-d arrays

Since indexing into a 0-d array with an integer is impossible,
we can disable any conversion/interpretation is integer code
to special case the 0-d array for now and fix this annoying
issue...
WIP,BUG: Fix outer iteration bug.
Attempt to start optimizing setmap
Followup stuff
Start trying to include operand into iterator
Working on a thourough rework of mapiter
Working mostly now, need to plug back in the exposed API
Further fixups
Fix bugs with old mapiter compatibility