Add support for .sbv (Youtube subtitles)

[dtmpsc]

Youtube seems to have dropped the ability to download a video's subtitles as an srt and now only offers their own sbv. I've used Jubler to stripout the timecode info for creating a text script. The workaround is to convert the sbv to srt here: https://gotranscript.com/subtitle-converter, then using Jubler. Seems like an easily fix to add sbv support. Thanks for creating this useful program.

[teras]

if you can provide me with clear documentation of sdv, or even better have the regex that supports this format, I'll be happy to implement it.

[teras]

Next version of Jubler will support this format. Stay tuned