Expand g_log_structured docs a bit
Expand g_log_structured docs a bit

Mention two possible pitfalls that were pointed out by Ray Strode.

johne53/MB3Glib,endlessm/glib,johne53/MB3Glib,endlessm/glib,endlessm/glib,endlessm/glib,johne53/MB3Glib,johne53/MB3Glib,johne53/MB3Glib,endlessm/glib,johne53/MB3Glib