PL: whitespace fixes
BF: proper from_any from filename
BF: use the new name for NIML support ("niml" instead of "niml_dset")
ENH: proper error message when query engine not trained
NF: surface-based voxel selection supports a new argument, "minimal_mapping", that when set to True returns a mapping from nodes to sets of voxels so that each voxel is associated with at most a single node