make lasagne.utils.concatenate support negative axes.
make lasagne.utils.concatenate support negative axes.

mheilman/Lasagne,gabortakacs/Lasagne,rlkelly/Lasagne,dnuffer/Lasagne,diogo149/Lasagne,cancan101/Lasagne,DataFighter/Lasagne-tutorial,ErnstHowie/Lasagne,Richi91/nntools,kracwarlock/Lasagne,MihailoIsakov/fishfish,DeanChan/Lasagne,ebattenberg/Lasagne,takacsg84/Lasagne