Seeds non-data model GUID generator during Experiment model initialization.
Set global user_id variable on PsychoCoffee object.
Replaces all seed references with user_id + "instance identifier" + model.id
Changes user_id to be inherited down subviews.
Adds ExperimentParameter model.
Fixes diff function to not accidentally reassign itself.
Fixes diff function to deal properly with non-object arrays.
Set user_id on subviews in initialization.
Properly inject parameterization down experiment, block, trial
hierarchy.