By Humeyra Pamuk ADIYAMAN, Turkey (Reuters) - In a small teahouse in the conservative southeastern Turkish town of Adiyaman, two brothers would hold court with young followers, praying, reading the Koran and painting a picture of a better life across the border in Syria, in the ranks of Islamic State. Adiyaman, though clearly poor and offering scant employment to the young, is an unremarkable Anatolian town of narrow streets, kebab houses, small shops and tea houses where men linger over backgammon.