Handle BIDS components more carefully
Handle BIDS components more carefully

when reading in the group csv file.

Hopefully fixes #351

oesteban/mriqc,poldracklab/mriqc,poldracklab/mriqc,oesteban/mriqc,poldracklab/mriqc,oesteban/mriqc,poldracklab/mriqc,oesteban/mriqc