Support Version 8 of the HLS specification

[dcoufal]

Description

Ideally, mamba would support all HLS tags through version 8.

This issue is more of a epic, and each tag would be a specific sub issue. If you decide to peel off a unsupported tag, make a new issue and link back to this one.

Tasks

For each tag

• Add the tag to PantosTag
• Add any data keys needed for the tag in PantosValue
• Add a new HLSTagValidator if needed.

References

• Preliminary spec available at https://developer.apple.com/streaming/HLS-WWDC-2017-Preliminary-Spec.pdf

• Older HLS specs available at https://tools.ietf.org/html/draft-pantos-http-live-streaming-23