ENH Label:  option to expand label from source space to surface
TEST:  Label in src
ENH Label in src:  fill in values from closest vertex
ENH setup_source_space:   option to run add_source_space_distance
FIX test_source_space:  subjects_dir
ENH Label in source space:  raise exception if not all vertices are in source space
ENH Label:  add .fill() method to fill surface from source space
WIP ENH stc_to_label:  add 'patch' option for smooth parameter
FIX test_stc_to_label
DOC:  whats-new
FIX:  use fixes.in1d
FIX Label:  source spaces without distances
API Label:  move source space completion into .fill() method
TEST:  remove redundant test
ENH: Add plot_trans function
API:  deprecate old label smoothing in stc_to_label()
DOC fix
ENH: Moving _find_trans to transforms.py to avoid circular import
TEST:  make warning test more lenient
DOC: Added plot_trans to whats_new