Switches from Backbone Relational to Backbone Associations.
Move prototype trial object into root of TrialObject folder.
Creates Image trial object.
Converts all models to use Backbone Association.
Refactors relations.
Implements Polymorphism for TrialObject collection.
Updates clock module to include requestAnimationFrame shim.
Calculates tick from set framerate.
Renames all instances of @count to @frame.
Adds pause and resume timer methods.
Use setTimeout to run triggers.