We need to be able to analyze corpora with time resolution below day (ex. for AMULEX project). This improvement would :

• the possibility to add three meta-data to a doc : hour, minute, second
• add hour, minute & second in the drop down of the phylomemy parameter panel so that we can analyze dynamics at the granularity of on of these units.
• check that when choosing these units, the dates in the phylemomy vizualization are rightly labelled (for @karenkonou ?)