reload table when data arrives
use fetchIfNeededInBackgroundWithBlock for lazy load of user

- the user isn't loaded until the audioClip is displayed in the table
  cell
add reloadData for table as soon as audioClips arrive

- this means we can immediately display the title and createdAt
  attributes
Merge pull request #30 from maml/associate-user-with-audioClip

Associate user with audio clip