Changes in 'ElectreCriteriaInteractionsConcordance':
* adaptation to 'alternatives vs profiles' scenario
* module renamed to 'ElectreConcordanceWithInteractions'
* 'get_criteria_interactions' moved to 'common.py'
* input files are now in underscore notation

Changes in ElectreConcordance:
* added 'two_way_comparison' in order to reduce redundant calculations
* input files are now in underscore notation

Some minor fixes in 'common.py'.