ENH as_ndvar():  automatic conversion of mne Epochs and Evoked objects
FIX clustering for NDVars without time axis
FIX WxTerm:  Show() shell when focusing prompt or resizing
FIX default sensor layout:  correctly center layout
ENH SelectEpochs():  convert data parameter with asndvar()
FIX SelectEpochs():  vlim initialization parameter
TEST/DOC:  Dataset.update()
TEST:  FIX test_examples