* Country riven by Muslim vs Christian violence
* In town of Boda, Muslims besieged
* Millions of people in need of aid, UN says
By Emmanuel Braun
BODA, Central African Republic, April 18 (Reuters) - In normal times, the rickety wooden bridges at each end of the red-dirt main street in Boda were gateways to shops and a bustling market in the diamond-mining town in Central African ...