bug in templates

Unit tests stopped working today.

Yesterday they were working: https://git-r3lab.uni.lu/NCER-PD/scheduling-system/-/jobs/10720

Today they crash: https://git-r3lab.uni.lu/NCER-PD/scheduling-system/-/jobs/10722

After investigating the reason is December month ;). Not sure how to fix it though. Here is the line responsible: https://git-r3lab.uni.lu/NCER-PD/scheduling-system/blob/master/smash/web/docx_helper.py#L15

The issue is that it tries to replace ##DATE_FULL## with something like: "vendredi 01 d�cembre 2017". There is some strange ascii character in the replacement. Maybe it should be casted to unicode??