Added the initial hinting structure

* Moved playInstructions and other calls to pbskids.Game
* Created the structure for tier and random hinting
Fixed the hint destroy function
updates to hinting module
Replaced game Animator with display's animator property
Fixed private Animator API call with public one
allow passing single string to tracked animator calls for synced audio and animation
include complete changes from last commit
Updated docs
Merged 'feature-hinting' branch