to address #222: comment out imgmath extension from sphynx (build errors on readthedocs)
to address #222: comment out imgmath extension from sphynx (build errors on readthedocs)

NYUCCL/psiTurk,NYUCCL/psiTurk,suchow/psiTurk,suchow/psiTurk,NYUCCL/psiTurk,suchow/psiTurk