conversion of 04 famille in progress

work done at 66%. Problems with handling empty generated dataframe and
concat.
Merge branch 'dev' of https://github.com/openfisca/openfisca into dev
Because of unfound error, started conversion of 04_famille from scratch.

The file has now implemented function to monitor the state of the data frame famille.
Merge branch 'dev' of https://github.com/openfisca/openfisca into dev
Correcting bug in 03_fip.py. Continuing translation of 04_famille.

Problem with the column declar1 of data frame famille.
04_famille converted, now with some self-checks
Started conversion of 07_invalides.py
Merge pull request #225 from jsantoul/dev

04_famille totally converted, now with some self-checks