Using include does not respect subfolders

[DavidBrainard]

It seems that if I (e.g.) specify the BrainardLabToolbox as include record, the subfolder list is not respected -- I get the whole thing. I have to specify the git type and URL to get the subfolder list to be used.

It isn't entirely clear what the precedence order ought to be in the include case (the subfolders specified in the included record, or those in the record asking for the include), so maybe the current behavior is the most reasonable. But in most use cases I can think of, I'd want the subfolders in the included record to rule.

[JorisVincent]

Pull request #84 partly fixes this: it at least respects the subfolder list specified in the record of the included toolbox.