* [Vision] Add bindings for Xcode 9 Beta 1 & 2
This commit also adds two convenience overloads to GetAttachments
that allows you to get a more strongly typed version of the
returned dictionary, this is needed because there is no easy way
to downcast from NSDictionary to NSDictionary<TKey, TValue>
and it is used in the sample that excecises the Vision API found here
https://github.com/dalexsoto/FaceDetector
* [Vision] Implement feedback
* Add commas to enums to avoid diff spam
* Throw a managed exception when we fail to dinamically call Vision framework
* [Vision] Update to xcode 9 Beta 3
* [vision] fix VNImageCropAndScaleOption enum
Also removed public modifier from enums in order to have interfaces
and enums in sync
* [Vision] Add missing comma to enum
* [Vision] More API enhancements
* Removed default .ctor from types that are not user created
* Added Strong Dictionary to VNImageRequestHandler ctors
* Turned VNImageOption into a StrongDictionary
* Added bug report[1] for BarcodeDescriptor so we do not forget
* Removed duped metadata from manual bindings
* VNDetectedObjectObservation subclasses now have the factory
method FromBoundingBox inherited from its parent class
(VNDetectedObjectObservation).
[1]: https://bugzilla.xamarin.com/show_bug.cgi?id=58197
* [Vision] Merge extern API with wrappers, fixed intro!
* [Vision] Add one missing public accessor to VNUtils