BUG: cannot convert invalid sequence index to tuple

A sequence which raises an error on item getting, should be just
handled as a single index and not a tuple nd-index.

Also fix some error handling.

closes gh-5063
TST: Test tuple subclass index and broken sequence index
ENH: Allow ravel to reshape in place when possible

This fixes a lot of corner cases in reshape 'K' when the array
is not contiguous in the first place, it was previously never
ravelled in place.

Closes gh-5033