New attempt : adding legislation
redundant test erazed from test_cot_soc (already in test_irpp.py)

2013 added in param xml for test_irpp.py

Changed if for PFL (the condition is the date insted of finpfl)

Actualized various date.

Solved some commented test in test_irpp.py

f2da commented because some tests doesn't pass
Non working test in test_irpp.py are commented, TODO have been added

utils.py have been enhanced for the browser search
Remove numerical_and with three parameters because they don't work.
Add labels to columns.
Ensure that entities with children have always the roles for the 2 parents even when there is only one.
Correct caseT suggestion: Put it in "foyer fiscal" instead of "individu".
transform _creimp in dateformula format instead of simpleformula (function
changed in irpp_credits_impots.py, dictionnary aded in model.py)
Amending test from taxip to work with yield
Fix 2DC bug !
Use legislation accessors (instead of _P) for irpp_charges_deductibles functions.
Use legislation accessors (instead of _P) for irpp_plus_values_immo & irpp_reductions_impots functions.
Re-add missing _P parameter.
Use legislation accessors (instead of _P) for isf functions.
Use legislation accessors (instead of _P) for lgtm functions.
Extract function mark_weighted_percentiles from statshelpers.
Use legislation accessors (instead of _P) for mini functions.
Don't fail in _ars when there is no children.
Rename and rearrange various sections of imput_variables
Add scripts to use Impôts simulator.