ENH plot ndvar:  add Xax and ds arg to all plotting functions
ENH Sensor dim:  add x, y and z properties
API tests/tables:  break up analyze package and make top level modules test, testnd and table
FIX plot.sensor:  marking ROI (&TEST)
ENH datasets:  get_rand() to replace other dataset constructors
WIPDOC/ENH plot:  unified subplot layout for most plots (&TESTs)
WIP plot:  adapt kwargs of plots not adopting layout yet
ENH SelectEpochs:  page turning with arrow keys; show busy cursor
ENH SelectEpochs:  .auto_reject() method with more options
ENH ndvar:  __init__ ravel arrays as long as they are 1 dimensional
FIX data-obj:  sorting (&TEST)
WIP ENH mne_experiment:  state levels
API mne_experiment:  tier yields value(s) on the variables over which it iterates
ENH mne_experiment:  rescan parameter in .set()
TEST load.fiff:  epochs from raw
API load:  make unrelevant names private
FIX plot.brain.stat():  only clean_time_axis if data has time axis
FIX ndvar repr
ENH mne_experiment:  set_env() on __init__
ENH mne_experiment.state(): don't show long (>60 chars) values