Added methods to allow setup and realtime triggering of recording.

AERecorder:
- (BOOL)prepareRecordingToFileAtPath:(NSString*)path fileType:(AudioFileTypeID)fileType error:(NSError**)error;
void AERecorderStartRecording(AERecorder *THIS);

AEAudioFileWriter
- (BOOL)createFileAtPath:(NSString*)path fileType:(AudioFileTypeID)fileType error:(NSError**)error;
void AEAudioFileWriterStartWriting(AEAudioFileWriter* THIS);
Added methods to trigger channel playback on realtime thread:
	void AEChannelSetPlaying(AEAudioController *THIS,id<AEAudioPlayable> channel,BOOL playing);
	void AEChannelSetPlayingAtIndex(AEAudioController *THIS,int index,BOOL playing);
Made _recording public
Reordered calls in AEChannelSetPlayingAtIndex()