Reload playlists when EXT-X-ENDLIST isn't present
Modify the parser to include an attribute when the endlist tag shows up in a media playlist. Update test playlist parses to add the attribute where appropriate. Trigger a playlist reload and merge if endlist isn't present in the parse. Clean up some formatting.
Track the media playlist URI when inferring a master playlist
When a media playlist was loaded directly, the URI wasn't being set on the implicit master playlist created by the plugin. That meant that playlist reloads weren't being correctly associated with the old playlist version and merges weren't happening. Now, live media playlists loaded directly should be updated properly after being refreshed and segment URLs are resolved directly against the media playlists when the master playlist is only inferred.