Hi,

I've begun using this extension for some manifest file manipulation, but come across a small issue where I'm using a non standard extension within the HLS spec that's been implemented by Wowza and JWPlayer.

The functionality adds an extra parameter to #EXT-X-STREAM-INF called Name which is added by Wowza and used by JWPlayer to show a more useful name for the variant in a client's quality selector. See http://support.jwplayer.com/customer/portal/articles/1430240-hls-adaptive-streaming

Note this shouldn't be confused with Name in the #EXT-X-MEDIA.

Would you accept an PR to add this functionality? It would add a Name field added to VariantParams struct (similar to the same tag in Alternative struct), additional support in decodeLineOfMasterPlaylist and (p *MasterPlaylist) Encode, along with corresponding tests, and sample-playlist.

Sample playlist:

#EXTM3U
#EXT-X-VERSION:3
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1828000,NAME="4 high",RESOLUTION=896x504
chunklist_b1828000_t64NCBoaWdo.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1378000,NAME="3 med",RESOLUTION=768x432
chunklist_b1378000_t64MyBtZWQ=.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=678000,NAME="2 med",RESOLUTION=512x288
chunklist_b678000_t64MiBtZWQ=.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=438000,NAME="1 low",RESOLUTION=384x216
chunklist_b438000_t64MSBsb3c=.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=128000,NAME="0 audio"
chunklist_b128000_t64MCBhdWRpbw==.m3u8