* Bangui mayor beats son of former president in run-off vote
* 'Anti-balaka' militia spokesman welcomes election of Samba-Panza
* EU foreign ministers agree to send up to 1,000 troops
By Paul-Marin Ngoupana
BANGUI, Jan 20 (Reuters) - Central African Republic's transitional parliament elected the mayor of Bangui, Catherine Samba-Panza, as interim president on Monday, tasked with ending ...