Added unit tests for SegmentList.
Added unit tests for SegmentList.

Changed the current tests for SegmentList and added new tests that
include testing SegmentTimelines.

Change-Id: I82e6429f31f396ba065aaae89bd95a1149a942ac

shaka-project/shaka-player,ustudio/shaka-player,shaka-project/shaka-player,treejames/shaka-player,indiereign/shaka-player,TheModMaker/shaka-player,ustudio/shaka-player,russitto/shaka-player,priyajeet/shaka-player,TheModMaker/shaka-player,brightcove/shaka-player,blinkbox/shaka-player,russitto/shaka-player,TobbeEdgeware/shaka-player,blinkbox/shaka-player,treejames/shaka-player,vimond/shaka-player,ustudio/shaka-player,cmgrecu/shaka-player,priyajeet/shaka-player,baconz/shaka-player,TobbeEdgeware/shaka-player,vimond/shaka-player,samdutton/shaka-player,samdutton/shaka-player,indiereign/shaka-player,priyajeet/shaka-player,TobbeEdgeware/shaka-player,treejames/shaka-player,sanbornhnewyyz/shaka-player,intfrr/shaka-player,intfrr/shaka-player,samdutton/shaka-player,intfrr/shaka-player,shaka-project/shaka-player,cmgrecu/shaka-player,indiereign/shaka-player,tvoli/shaka-player,Ross-cz/shaka-player,UIKit0/shaka-player,treejames/shaka-player,Afrostream/shaka-player,shaka-project/shaka-player,ustudio/shaka-player,priyajeet/shaka-player,vimond/shaka-player,samdutton/shaka-player,TheModMaker/shaka-player,sanbornhnewyyz/shaka-player,tvoli/shaka-player,sanbornhnewyyz/shaka-player,Afrostream/shaka-player,brightcove/shaka-player,blinkbox/shaka-player,UIKit0/shaka-player,sanbornhnewyyz/shaka-player,TheModMaker/shaka-player,Ross-cz/shaka-player,tvoli/shaka-player,Afrostream/shaka-player,tvoli/shaka-player,UIKit0/shaka-player,cmgrecu/shaka-player,intfrr/shaka-player,brightcove/shaka-player,baconz/shaka-player,Ross-cz/shaka-player,UIKit0/shaka-player,russitto/shaka-player,baconz/shaka-player,blinkbox/shaka-player,Afrostream/shaka-player