Raise error if using merge_mode= with unnamed input
Raise error if using merge_mode= with unnamed input

DeepGnosis/keras,fmacias64/keras,amy12xx/keras,Aureliu/keras,kuza55/keras,keras-team/keras,stephenbalaban/keras,sjuvekar/keras,Smerity/keras,johmathe/keras,zxytim/keras,EderSantana/keras,ashhher3/keras,cvfish/keras,nebw/keras,xiaoda99/keras,kemaswill/keras,iamtrask/keras,printedheart/keras,untom/keras,abayowbo/keras,keras-team/keras,iScienceLuvr/keras,daviddiazvico/keras,imcomking/Convolutional-GRU-keras-extension-,dolaameng/keras,relh/keras,jimgoo/keras