dealing with BIDS phenotype directories

[dnkennedy]

While bidsmri2nidm can work with the BIDS phenotype directory, we ran across an example where the phenotype directory.
Specifically, the ABCD-ReproNim week 6 problem set, as described here, fails unless you remove the phenotype directory before running the bidsmri2nidm step.

@dbkeator mentioned when looking at this: "The BIDS phenotype directories are currently supported but what happened here is that each of those assessments in the phenotypes directory used exactly the same variable names which apparently is causing problems inside the code."