set feed's query limit to 10
(cherry picked from commit a5ca299f8c30a5c7ab50980b183fa6a712cda955)
remove query limit on feed items
add ClipAudioPlayer
import ClipAudioPlayer in FeedViewController
implement initWithContentsOfURL in ClipAudioPlayer
update type on property for player in FeedViewController
set query limit to 2
remove initWithContentsOfURL from ClipAudioPlayer
add ClipAudioPlayerDelegate protocol to ClipAudioPlayer
declare FeedViewController as conforming to ClipAudioPlayerDelegate
set FeedViewController as its player's clipAudioPlayerDelegate
implement clipAudioDidFinishPlaying in FeedViewController
synthesize clipAudioPlayerDelegate property in ClipAudioPlayer implementation
remove AVAudioPlayerDelegate method from FeedViewController
stop reversing audioClips in the block after they've been returned
order query for audioClips by descending on createdAt
complete rewrite of audio play for feed and ambient players

this commit basically is just trying to make it so interface concerns
wrt to audio are handled in the FeedViewController and audio playing
funcitonality is handled by separate audio player classes. this is made
possible by two protocols: FeedAudioPlayerDelegate and FeedViewDelegate.
Merge branch 'master' of github.com:maml/23seconds

* 'master' of github.com:maml/23seconds:
  remove query limit on feed items (cherry picked from commit e98d40ba601e3f00f04e563d449c5058f68ab928)
  set feed's query limit to 10