propagate None in conv_output_length, fix Conv1D and Conv2D with border_mode == 'same'
propagate None in conv_output_length, fix Conv1D and Conv2D with border_mode == 'same'

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