STY
RF:  make `data.stats` module
ENH load.besa:  add dat_file, dat_set and roi readers
ENH Factor:  .isin() and related methods
ENH Dataset: allow adding factor with slicing

>>> ds['name', :] = 'value'
ENH plot.UTSStat:  add xlim option
ENH permutation:  permute cases within categories
 WIP:  FIX stats:  Nested effects
ENH:  add table.difference
STY:  table argument names
FIX:  repeated measures table (table.repmeas)
ENH plot:  x-axis conversion (only applied to UTS plots)
FIX examples
ENH plot:  group colormaps
ENH load.besa:  separate path and data reading
FIX plot.UTSStat:  on plotting legend hide previous legend
API:  `compress` -> `aggregate`
ENH MneExperiment:  make_raw (use iir filters)
FIX plot:  legend
ENH:  add MneExperiment.make_copy()