move DateTil
simplify DateTil
enable DateTil from a DateTil
init PensionData
selected_date in PensionData
minor correction
use dateleg only (and datapension to come)

#TODO: surcote
doesn't run anymore
data in get_trimester

it will be a long process
data in calculate_pension
do something (wrong) with datesim in surcote
maximal use of data for get_trimester
data in calculate salref and calculate taux
more data
data in sali_for_regime
correction in datetil