* Only 900 left in Bangui, of former population over 100,000
* Only $87.6 mln donated toward UN aid appeal of $551 mln
* Tensions high in divided Boda, U.N. rights office says
By Stephanie Nebehay
GENEVA, March 7 (Reuters) - Fewer than 1,000 remain of more than 100,000 Muslims who once lived in the capital of the Central African Republic, after a campaign of violence by Christian ...