-update ergonomic
- add v13 support instead of v4 one. I think that fragments are more
comprehensible than listfragment with v4 support. Unfortunately we still
need v4 support du to viewpager...
- finish v13 transfer
- use static method to obtain ID, firstname and lastname instead of
using a lot of intents.
Explications : I could use sharepreferences, serialization or Sqlite but
all that methods have one problem, they stored informations in files and
user can modify them if his phone is root...
- add sqlite comment before making synchronization when student post
their own comment