[ios] Make MGLCoordinateInCoordinateBounds() public

[friedbunny]

Makes the formerly-private MGLCoordinateInCoordinateBounds() function publicly available.

• The old private function converted MGLCoordinateBounds→mbgl::LatLngBounds and CLLocationCoordinate2D→mbgl:LatLng.
• The new public function compares CLLocationCoordinate2D and MGLCoordinateBounds directly.

/cc @1ec5

[friedbunny]

One potential issue I’ve encountered with this simplified function is that it strictly requires the bounds to be NE, SW. The old function would fix screwy bounds (e.g., where NW/SE was used) by creating a convex hull from that bounds’ points — essentially, always recreating the bounds.

[1ec5]

Looks good to me.

The old function would fix screwy bounds (e.g., where NW/SE was used) by creating a convex hull from that bound's points — essentially, always recreating the bounds.

We've also discussed flipped coordinates as a way of indicating a bounds that spans the antimeridian. Whatever the case, perhaps we need an MGLCoordinateBoundsStandardize(), by analogy with CGRectStandardize().