The output from load_afq_data is getting pretty busy

[richford]

load_afq_data already returns a tuple with up to 8 elements. Depending on how we resolve #78, this might climb up to 9 elements. This is too much and I often forget the order of the results. How should we simplify the returned result:

• Return a dict with keys X, subjects, groups, etc.
• Return a namedtuple. See os.stat for an example implementation from the standard library.
• Leave load_afq_data as is but also provide an AFQDataLoader class with attributes for each return value.

I'm partial to the namedtuple since it can be unpacked like a regular tuple so it would be backwards compatible. But we could also access the fields by name, much like a class instance's attributes. Kind of the best of both.

@arokem WDYT?

[arokem]

+1 for the namedtuple