* Remove the acceptableErrors system and replace with a status check
in SBM on request failure.
* End an SBM fetch task early on 404 or 410, but only during start
and switch.
* Retry segment fetch to recover from 404/410 errors sooner.
* Set retry delay based on segment duration.
* Remove the 'truncated' fetch mechanism and the 'pleasebuffer'
mechanism. (Retry is more robust than entering a buffering state.)
* Retry MPD requests as well. (Some live streams seem to experience
very transient 404 errors when requesting updates.)
Issue #21.
Change-Id: I2d3b838a9afe950e9ed0a91da9b952d8a30bf0a1
Joey Parrish