Fix Swift 4 warnings

This release removes the user credentials from a secrets.swift file to a settings screen.
Swift 4 warnings fixed.
This is the first step of several in preparation of releasing to the app store.

Private Pub/Sub

Changed publish and subscribe to us private setting.
Previously, these were public, so any other users with the same event name (eg. the default 'patriot' event name) would be visible to every other user.
This change requires that the Photon and Alexa code be updated to the latest updates also.

Initial release

This code implements the dynamic device detection.

You will need to rename and modify the secret-template.swift file to secret.swift with your particle.io credentials.

You will also need at least one Photon running a Patriot sketch on your account.