A class that wraps up writing and accessing files outside a Mac apps App Sandbox files into a simple interface. The class will request permission from the user with a simple to understand dialog consistent with Apple's documentation and persist permissions across application runs.
Adding 'void' in block prototype to remove compiler warning "This block declaration is not a prototype", see: https://stackoverflow.com/questions/47916585/objective-c-block-parameter-issue-this-block-declaration-is-not-a-prototype