message: Add example and small blurb about sigmoid layer.
diff: @@ -9,6 +9,16 @@ title: Sigmoid Layer
  * Header: [`./include/caffe/layers/sigmoid_layer.hpp`](https://github.com/BVLC/caffe/blob/master/include/caffe/layers/sigmoid_layer.hpp)
  * CPU implementation: [`./src/caffe/layers/sigmoid_layer.cpp`](https://github.com/BVLC/caffe/blob/master/src/caffe/layers/sigmoid_layer.cpp)
  * CUDA GPU implementation: [`./src/caffe/layers/sigmoid_layer.cu`](https://github.com/BVLC/caffe/blob/master/src/caffe/layers/sigmoid_layer.cu)
  +* Example (from [`./examples/mnist/mnist_autoencoder.prototxt`](https://github.com/BVLC/caffe/blob/master/examples/mnist/mnist_autoencoder.prototxt)):
  +
  + layer {
  + name: "encode1neuron"
  + bottom: "encode1"
  + top: "encode1neuron"
  + type: "Sigmoid"
  + }
  +
  +The `Sigmoid` layer computes `sigmoid(x)` for each element `x` in the bottom blob.
  ## Parameters
  