Auto extend media playlist, expose winsize, set winsize 0 on VoD

[bradleyfalzon]

There are three related commits here all addressing issues.

Expose setter and getter for media playlist winsize

0f55de0 fixes #53 and finishes #22, this exposes two new methods for a media playlist, SetWinSet() and WinSize() which sets and gets the winsize respectively.

Auto extend media playlist when decoding without a media playlist

78a4147 fixes #5, when decoding a playlist using the Decode() or DecodeFrom() functions (not the equivalent methods on a Master/Media Playlist), the decode function would create a new media playlist with a winsize of 8 and capacity of 1024. If the playlist was >1024 segments, the remaining segments would be dropped.

This auto extends the playlist in this case (not when using the media playlist decode methods) but doubling its size each time. In no other cases are playlists extendable.

Set winsize 0 on VoD/EVENT playlist when decoding without media playlist

25316cc addresses #53, related to the previously mention commit 78a4147, this also changes the winsize from 8 to 0 for VoD and EVENT playlists to display in full.

[bradleyfalzon]

@grafov are you able to look over these changes, in particular the auto extending playlist? I've spent some time on it, and I'm confident with the change and all tests to check this new behaviour.

This should then allow us to close off the 3 mentioned issues.

[grafov]

Sorry for delay. I reviewed these changes and not see any problems. I think proposed way for autoextending playlists is good and it keeps old API. Let use it. Thank you very much!