Some functions have deprecated due to packages update. #530

Hi, when I use BrainIAKto to load some data, I got some error:

get_data() is deprecated in favor of get_fdata(), which has a more predictable return type. To obtain get_data() behavior going forward, use numpy.asanyarray(img.dataobj). * deprecated from version: 3.0 * Raises as of version: 5.0

It seems like due to some nibabel function's usage has changed, but the built in functions of BrainIAK did not. Would you mind to update the built in functions of BrainIAK in order to reduce error?