Refactoring to a Data Manager

In this episode we clean up some autolayout warnings, implement some changes to support dynamic text, then move our attention to presenting the podcast detail screen when tapping on search results. Since the data is coming from various places we introduce a Data Manager to move that responsibility out of the view controller.

This is a companion discussion topic for the original entry at https://nsscreencast.com/episodes/398-podcast-app-data-manager