Taking care about variables

Variables must exists before trying to insert them
into the json tree.
Simplifying a bit the code by cutting it into
functions.
New file where all unpacking code will go.

Tha file packing.h is shared for the packing and unpacking
functions as creating a new unpacking.h file is not absolutely
necessary for now.
Unpacking things.

This is a test code, to see if things can work like that.
Communicating between client and serveur.