Refresh token

Refresh the tokens:

provider.refreshToken { result in
    // ...
}

Check if a token is valid:

if let token = provider.token {
    print(token.isValid)
    print(token.isExpired)
}

Optionally set the scopes:

provider.scopes = ["some", "scope", "here"]

Optionally set the additional parameters for the authorization/token requests:

provider.additionalAuthRequestParams
provider.additionalTokenRequestParams

A new wiki 😃