EHN. corrected docstrings

better examples
Merge pull request #72 from pburdet/ENH_spectrum_3D_dimension

Fixes #70. EHN: to_image and to_ spectrum modified.
EHN background image spectrum for 2D

add manually in plot() a background
Merge branch 'ENH_background_for_plot' into NEW_edsSpectrum
EHN background image spectrum for 2D

add manually in plot() a background
Merge branch 'master' into NEW_edsSpectrum
Merge branch 'ENH_background_for_plot' into NEW_edsSpectrum

Conflicts:
	hyperspy/signal.py
EHN max and min for signal

create max and min similar to mean
Merge branch 'ENH_max_min' into NEW_edsSpectrum
Merge pull request #73 from pburdet/ENH_max_min

EHN max and min for signal
Correct small typos in docstring
Fixes #74
Fixes #75
Merge branch 'master' into NEW_edsSpectrum
EHN elements dictonary for EDS

add a dictionnary and modified add_elements
EHN: implementation of EDS_TEM and EDS_SEM

to_EDS('SEM'), read param in original_parameters,
set_microscope_param with ui
EHN creation of subclasses EDSSEMSpectrum and EDSTEMSpectrum

adapation of set_microscope_parameters, get_calibration_from, msa