[Scenario] Timeline Rollout 2 Update

Contains various fixes for Rollout 1.5 & 2, along with initial implementation for Scenario rollout

Includes bug fixes to support nasa/MCT-Plugins#8 (particularly, to ensure synchronization between changes in Inspector and changes in a Timeline View on center panel)

Also includes initial implementation for nasa/MCT-Plugins#13 (note that this object/view type has been suppressed in this pull request)