add eos and UNK to internal datastructures
add eos and UNK to internal datastructures

emjotde/amunmt,emjotde/amunn,emjotde/Marian,amunmt/marian,DianaDespa/marian-train,emjotde/amunmt,emjotde/Marian,marian-nmt/marian-train,emjotde/amunn,amunmt/marian,marian-nmt/marian-train,DianaDespa/marian-train,emjotde/amunmt,DianaDespa/marian-train,DianaDespa/marian-train,emjotde/amunn,marian-nmt/marian-train,emjotde/amunn,amunmt/marian,marian-nmt/marian-train,emjotde/amunmt,marian-nmt/marian-train,DianaDespa/marian-train