fixed a bug in bnt.yap: the index of the value of the evidence variable start from 1 rather than from 0
added the possibility of computing the marginal of more than one variable in bnt.yap
git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@2103 b08c6af1-5177-4d33-ba66-4b1c6b8b522a