Use promises to facilitate counting and success calls
Less is special about the way that expectations work.  They use the same loader now like everything else
Less fat arrows in BrainstemExpectation
Less fat arrows in the StorageManager
Less fat arrows in Utils
Remove unused function from LoadingMixin and use this instead of @ when passing it as a value
Remove fat arrows from Brainstem.Model
Remove fat arrows from BrainstemCollection
Git rid of the DataLoader concept as it was not buying us much