Basic Ad Stitching Support

## Demos:
* Syndication Mode:
** midroll syndication stream ( no player client lib ) 
* Hybrid Mode:
** Preroll with ad sequence session for video stream, and client side everything else. 

Demo implementation notes:

*No php start_session calls, uses stateless unique user id as session key. 
** minimal php includes integrates AutoLoader.
*Fully integrated ad ingest and fallback to standard ad playback, 
** system ingests ads into kaltura to deliver them in HLS. 
* Modular back end streaming component class ( most HLS specific stuff in its own class ) , could support adding in MPEG-Dash support when the time comes
* Socket based debug interface
**No dependencies on sockets for VOD ad stitching request flows ( just used for realtime debugging ). 
** simple php based version now, but basically any socket implementation that could access cache and uuid could insert actions for live.
* Fully hybrid player sequence mode support
** Client makes ad requests in sequence mode ( per our high level design diagram )
** Virtualized playhead / player states, for client side analtyics and ad beacons ( cross domain cookie support / client origin requests )  
* Leverages existing infrastructure:
** player uiconf parsing, and runtime argument handling ( flashvars )
** ad requesting proxy (x-forward-for etc. )
** “extends" KalturaAdPlayer javascript library for hybrid mode. ( ad click, ad skip, vast 3 icons, etc ) 
** leverages unified ad config, i.e the same ad config you do today in the KMC seamlessly crosses over to ad  
** stitching urls once passed that uiconf id.