title: print out the shape of each layer in the net architecture
body: <p>In Keras, we can define the network as follows. Are there any way to output the shape after each layer. For instance, I want to print out the shape of <code>inputs</code> after the line defining <code>inputs</code>, then print out the shape of <code>conv1</code> after the line defining <code>conv1</code>, etc. </p>
  
  <pre><code>inputs = Input((1, img_rows, img_cols))
  conv1 = Convolution2D(64, 3, 3, activation='relu', init='lecun_uniform', W_constraint=maxnorm(3), border_mode='same')(inputs)
  conv1 = Convolution2D(64, 3, 3, activation='relu', init='lecun_uniform', W_constraint=maxnorm(3), border_mode='same')(conv1)
  pool1 = MaxPooling2D(pool_size=(2, 2))(conv1)
  
  conv2 = Convolution2D(128, 3, 3, activation='relu', init='lecun_uniform', W_constraint=maxnorm(3), border_mode='same')(pool1)
  conv2 = Convolution2D(128, 3, 3, activation='relu', init='lecun_uniform', W_constraint=maxnorm(3), border_mode='same')(conv2)
  pool2 = MaxPooling2D(pool_size=(2, 2))(conv2)
  </code></pre>