Add "begin" and "end" dates to legislations to be able to apply legislations outside their given dates by extending them.
Add missing log declaration.
Accept a year instead of a full birth date.
Add OpenFisca-France GitHub to requirements.
Fix bug causing travis build error

https://travis-ci.org/openfisca/openfisca-france/builds/19532118
ISF : small corrections and tests
small changes in rfr
Add a test for retraites
Improve tests on seniors.
Adding some cerfa_field.  Typo in datatrees
Update datatrees.py
Update .travis.yml
Fixing csg_deduc_patrimoine

test_cotsoc_sal_cap
Update .travis.yml

Fix typo
Cleanup code and remove invalid use of dictionnary update.
Move tests inside the package
Adding cerfa_field for indvidual foyer variables
Add preprocessing of legislation_parameters
Spelling.
Add missing 'u' prefix for string litterals.