Added numberOfFilesInLevel for use in testing
Added numberOfFilesInLevel for use in testing

zhengkejun/leveldb,kenwenzel/leveldb,ljyloo/leveldb,dain/leveldb,kenwenzel/leveldb,maxboehm/leveldb,cdapio/leveldb,mashuai/leveldb,archiecobbs/leveldb,rnarubin/leveldb,xuzha/leveldb,gaoch023/leveldb-1