catch exceptions from open and send and reject the load promise
restricts the size of the generated segment list for SegmentTemplate mpd's
restricts the size of the generated segment list for SegmentList mpd's
restricts the size of the generated segment list for SegmentTimeline mpd's
removes extra attempts to make a HEAD request during live edge search
fixes range calculation for generated segment list for SegmentTemplate mpd's
fixes jshint error