* Meth use has increased greatly in Iran in recent years * Addiction linked to lack of understanding about the drug * Some success in treatment of meth addicts * But country still faces a tough battle By Babak Dehghanpisheh BEIRUT, Dec 8 (Reuters) - Women in headscarves and men in tatty clothes puff on a glass pipe as ***** swirls around their faces. The pictures published by Iranian media and blogs in recent months are a sign of a new drug epidemic: shishe, or methamphetamine. Shishe means "glass" in Farsi, a reference to the appearance of the drug in some of its purest forms. ...