demo: Fix project dependencies, fix #11.
DOUAudioEventLoop: Remove outdated `FIXME`.
DOUAudioStreamer: Add `bufferingRatio` (KVO).
Add `DOUAudioStreamer+Options`.

- DOUAudioStreamerKeepPersistentVolume
- DOUAudioStreamerRemoveCacheOnDeallocation
Publicize `kDOUAudioStreamerBufferTime`.
DOUAudioFileProvider: Add `mimeType` & `fileExt`.
DOUAudioPlaybackItem: Fallback with type hints.
Update example.
DOUAudioStreamer: Add `sha256`.
Update example.
DOUAudioEventLoop: Fix audio route change.
Revert "Merge pull request #9 from tonycn/master"

This reverts commit 3241540e837536f485e1139b970160b459d42820, reversing
changes made to ac6191964e59fb5378f007c132344f1e35939f32.
Fix interruption handling.

Fix #17.
DOUAudioFileProvider: Refactor remote `isReady`.

Fix #16.
DOUAudioEventLoop: Fix audio route change.

Only pause the streamer when headphones are unplugged.
DOUAudioFileProvider: Consider non-optimized file.
example: Includes 64-bit arch and targets iOS 7.
DOUAudioEventLoop: Add `-Wdeprecated`.

AudioSession related APIs have been marked as deprecated as of iOS 7, we
might switch to the higher level AVAudioSession some day in the future,
but not now.
DOUAudioVisualizer: Suppress conversion warnings.
DOUAudioPlaybackItem: Suppress a conversion warning.

Close #20.