ENH testnd:  duration based cluster correction
FIX SelectEpochs:  remove bad sensors from mean seg
FIX/ENH SelectEpochs:  layout;  nplots arg, DOC
ENH SelectEpochs:  disable next/back buttons at extreme pages
FIX colorspaces:  pickle without matplotlib colormap
FIX ndvar:  add .shape attr
FIX dataset.save_txt():  header=False
ENH wxterm:  app look for Debug in config;  implement MacReopenApp().
FIX wxterm:  py-editor suggestions popup
FIX wxterm:  close all plots