Parse EXT-X-CUE-OUT and EXT-X-CUE-IN

[birme]

This PR extends the parser with the ability to handle EXT-X-CUE-OUT and EXT-X-CUE-IN.

#EXT-X-CUE-OUT:DURATION=30
#EXTINF:10,	
#EXT-X-BYTERANGE:709136@5212676
hls_450k_video.ts
#EXTINF:10,	
#EXT-X-BYTERANGE:730004@5921812
hls_450k_video.ts
#EXTINF:10,	
#EXT-X-BYTERANGE:456276@6651816
hls_450k_video.ts
#EXT-X-CUE-IN
#EXTINF:10,	
#EXT-X-BYTERANGE:468684@7108092
hls_450k_video.ts

EXT-X-CUE-OUT duration is available as PlaylistItem.get('cueout') and indication of EXT-X-CUE-IN as PlaylistItem.get('cuein')