* Most conciliatory statement yet by Serbia's Nikolic
* Surprise comments follow Bosnian Muslim leader's visit
* Serbia in line to start EU accession talks
By Daria Sito-Sucic
SARAJEVO, April 25 (Reuters) - Serbia's nationalist president has implored forgiveness for the 1995 Srebrenica massacre in Bosnia, in his deepest apology yet for crimes committed by Serbs in the wars that ...