ENH ClusterDist:  slices of TFCE results
DOC testnd:  better error message for invalid kwargs
ENH SourceSpace:  allow .index_for_label() with string
FIX plot.topo:  vmax & vmin kwargs
FIX plot.topo:  **layout kwargs
ENH SelectEpochs GUI:  GA button to plot Grand Average
FIX SelectEpochs:  key-press over no axes
ENH Dataset.aggregate():  ADD equal_count argument
API Factor:  cells in tuple instead of list, LazyProperty
FIX Celltable:  numerical `X` and `cat`
ENH t_contrast:  allow cells with "*"
ENH TreeModel:  compounds

automatically update compounds composed of different elements, skipping
elements that are = ""
ENH MneExperiment:  `sns-kind` compound
ENH MneExperiment:  `evoked-kind` compound
ENH MneExperiment:  ADD option to equalize trial count in evoked files
FIX MneExperiment.load_events():  `edf` kwarg
FIX MneExperiment:  delete mne Raw from evoked-files
WIP SETUP:  use setuptools upload_docs
DOC:  changes
WIP MneExperiment:  test