This adds basic support for the EXT-X-MAP tag that has the Media Initialization Section necessary for a valid video.
Things that don't work yet, probably:
Discontinuities. When a new map comes, it would be written like any other segment, but probably should start a new file. Considering that hlsdl is only give one target file per launch, this would need some thinking.
Encryption. I haven't quite understood form the spec how does an init section behave in the presence of encryption, and what must be used as the key.
This adds basic support for the EXT-X-MAP tag that has the Media Initialization Section necessary for a valid video. Things that don't work yet, probably: