Since every manager *should* be using a DeviceFactory for managing
configuration, moved getFactory to Manager so that it can be accessed by
the application.
Changed Devices to give SortedSets of the paths to backup, since that's
what's being used internally anyways.
Created a ListModel for the backup paths of a device
Refactored the startup sequence for the app. Modularized it in case I
ever want to change how it works later down the road in a different
class (different FileStorePoller settings, for instance).