nitcorn: force delete session cookie when no session associated to response

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
nitcorn: harden request processing

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>
contrib: intro of tnitter

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>