fix(ng2.uiSrefActive): don't puke on sref to invalid target state
fix(ng2.uiSrefActive): don't puke on sref to invalid target state

wawyed/ng2,ui-router/core,ui-router/core,ui-router/ng2,codersongs/codersongs.github.io,fpipita/ui-router,ui-router/ng2,mattlewis92/ui-router,ui-router/angular,ui-router/angular,angular-ui/ui-router,mattlewis92/ui-router,wawyed/ng2,fpipita/ui-router,angular-ui/ui-router,fpipita/ui-router,ui-router/angular,ui-router/angular,codersongs/codersongs.github.io,wawyed/ng2,angular-ui/ui-router