* CLInterface - Added in the functionality to do everything the user
needs to do with podcasts, which includes: Updating the podcast listing,
Changing the status of a podcast episode (Set it to download, stop the
download, delete the episode)
* Podcasts - Added in checks to make sure no other podcast is
downloading at the same time, when an update is requested. Deletion of
episodes will occur in this class, as it will be a function used in both
the cli and the gui.