Show HN: iOS Login Screen Written in Swift 4

Not that you're asking for a code review but a couple things I noticed:

- You left your twitter IDs in your code. Not sure if it matters to you or not.

- Your buttons probably have some stuff in common (corner radius at least), so consider making the them all inherit from the base LoginButton class.

- You can put multiple lets on a single line, like `if let accessToken = AccessToken.current, let facebookAPIManager = FacebookAPIManager(accessToken: accessToken) {`

Hi there! I hope you're enjoying the template! Please let me know if you have any feedback or ideas for improvements! Thank you!