Add test to detect Enums without enumeration.
Replace tabs with spaces and remove trailing spaces.
Comment out column without enumeration and update datatrees.
Improve spelling.
Ignore some input columns that are not used in formulas.
Remove from datatrees the input columns that are not used in formulas. Improve detection of such columns in test_columns.
Merge pull request #100 from adrienpacifico/master

changed an error that prevented the first test to execute.
Rename column "prenom" to "nom_individu" and add names to other entities.
Remove too stringent assert when importing survey dataframe