The timeline is now decoupled from the real time

The timeline is now decoupled from the real time

This commit allows the timeline to exist independently of the actual
time. This will allow it to be used to seek through an animation
with relative ease. We also made some architectural changes to the
timeline to support this.

Changes
=======
- Refactored the runner into its own file without exposing it to the
user (changed the gulpfile)
- The timeline no longer depends on the current time
- The user can supply absolute times to queue events
- Some more methods have been integrated into the timeline