- rename '_volurm_for' to 'map_to'. Remove dim1 and dim2 parameter: now useless because we can dircetly get them for the spectra class

# Conflicts:
#	est/core/process/process.py
#	est/core/process/pymca/test/test_io.py
#	est/core/process/test/test_roi.py
#	est/core/test/test_types.py
#	est/io/io.py
#	est/setup.py

# Conflicts:
#	est/core/types.py
#	requirements.txt

This require the creation of some helpers to link io and XasObject, this is the goal of xas.core.io.