FIX: honor OMP_NUM_THREADS environment variable
FIX: honor OMP_NUM_THREADS environment variable

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