You need to add the Wikitude Native SDK as 'Embedded Binary'. Just adding it as a Linked Framework is not enough. You also need to set EMBEDDED_CONTENT_CONTAINS_SWIFT to Yes.
If you still have issues then, since you are building on iOS 10, did you make sure to download our latest SDK version which offers support for iOS 10? In addition, did you follow the exact steps posted in our Unity documentation here?