Add metadata structure tree to User Guide.
Rename metadata.TEM -> metadata.Acquisition_instrument.TEM and metadata.SEM to metadata.Acquisition_instrument.SEM.
Automatic style corrections courtesy of autopep8.
Move title, date, time, original_filename to metadata.General
Automatic style corrections courtesy of autopep8.
Move metadata.signal_type to metadata.Signal.signal_type
Automatic style corrections courtesy of autopep8.
Move signal_kind, signal_origin and record_by to metadata.Signal. Move metadata.Variance_estimation to metadata.Signal.Noise_properties.Variance_linear_model and Signal.variance to metadata.Noise_properties.variance.
Automatic style corrections courtesy of autopep8.
metadata._Internal_parameters.folding -> metadata._Internal_parameters.Folding
metadata._Internal_parameters.stacking_history -> metadata._Internal_parameters.Stacking_history
metadata.Acquisition_instrument.TEM.EDS -> metadata.Acquisition_instrument.TEM.Detector.EDS, metadata.Acquisition_instrument.SEM.EDS -> metadata.Acquisition_instrument.SEM.Detector.EDS
Automatic style corrections courtesy of autopep8.
Change HyperSpy hdf5 format to version 1.2. The reader converts  to the new structure. However, v1.2 files cannot be read by HyperSpy 0.6.
Automatic style corrections courtesy of autopep8.
Update the User Guide.
Rename Xray_lines -> xray_lines in metadata.Sample.
Automatic style corrections courtesy of autopep8.
Move TEM.dwell_time and TEM.exposure to TEM.Detector.EELS.
Automatic style corrections courtesy of autopep8.