bigo: add support for hls streams
bigo: add support for hls streams

This is a fix for issue #1031 since FLV streaming is broken

gravyboat/streamlink,chhe/streamlink,beardypig/streamlink,beardypig/streamlink,streamlink/streamlink,bastimeyer/streamlink,javiercantero/streamlink,bastimeyer/streamlink,gravyboat/streamlink,back-to/streamlink,javiercantero/streamlink,melmorabity/streamlink,streamlink/streamlink,back-to/streamlink,wlerin/streamlink,wlerin/streamlink,chhe/streamlink,melmorabity/streamlink