Add 2014 to copyright years.
Replace descriptions with ordered dicts.
Cleanup code.
Add test to validate legislative parameters and comment incomplete parameter.
Move enumerations in their own module.
Move baremes into their own module.
Rename OpenFisca-Core utils module to statshelpers.
Always use unicode for labels of columns and prestations.
Remove unused Scenario._isPopulated.
Add "begin" and "end" dates to legislations to be able to apply legislations outside their given dates by extending them.