It was difficult to use the zero-parameter form of Timeline.schedule() with TypeScrip...

It was difficult to use the zero-parameter form of Timeline.schedule() with TypeScript. The .d.ts file didn't include the retuen type for a list of runner infos, and adding it still m,ade it harder than it should be to iterate over it type safely. In this commit I

1. Added the type information for `ScheduledRunnerInfo`, and updated the Timeline types to include it as a retuen type for `schedule`

2. Added a new function to Timeline, `getSchedule`, that simply returns the runner list. This seems to be cleaner than having the original `schedule` that can return two wildly different things.

I didn't remove the old functionality.