BUG-FIX: the hydrogenic xs were raising an exception when Z<13 and Z>36 because Egerton's original code was not designed to work out of this range
Add correction factor parameters for Na and Mg to the Hydrogenic XSs so that they better match HS XSs
EHN: add mass absorption
EHN: tidy up element_EDS
EHN: litterature
SUP: suppress all mass absorption coefficient
Merge branch 'master' into mass_absorption_coeff

Conflicts:
	hyperspy/_signals/eds.py
	hyperspy/misc/eds/elements.py
	hyperspy/misc/eds/utils.py
ENH:databse merging
Automatic style corrections courtesy of autopep8
SUP: supress old databases
Automatic style corrections courtesy of autopep8
ENH: modify where database is used
Automatic style corrections courtesy of autopep8
Merge branch 'DOC_improved_EDS' into ENH_merge_elements_EDS_EELS
DOC: some doc in eds
ENH: Li Ka energy
Automatic style corrections courtesy of autopep8
BUG: all dictBrowser as dic
Automatic style corrections courtesy of autopep8
Merge branch 'DOC_improved_EDS' into ENH_merge_elements_EDS_EELS