9.14.0.0 support

Now signs in under the 9.14.0.0 user agent, as Snapchat has cutoff support for earlier versions.

Warning—Please read

This release requires a method of login that sends the username and password of the Snapchat account over an unencrypted network to a remove server to generate a new header value for login. Because of the security risks involved, you must explicitly set the new useInsecureLogin property of SKClient to YES before signing in, or signing in will probably fail. If you have a tool or app that relies on this library, warn your users before continuing to use SnapchatKit.