private void btnConnexion_Click(object sender, EventArgs e)
{
Connexion connexion = new Connexion(tbEmail.Text, tbMdp.Text);
Requete maRequete = new Requete();
maRequete.SeConnecter(connexion);
String json = maRequete.GetResult();
FluxConnexion monFlux = JsonConvert.DeserializeObject <FluxConnexion>(json);
Form monForm = new FormListeContacts(monFlux);
this.Hide();
monForm.ShowDialog();
this.Close();
}