Simplify LeNet (#394)

* simpler lenet

* better version

* update & simplify

* update & simplify

* project+manifest

* use JLD2 and Flux.state

* make directory, tidy

* manifest

* add show statements

Author: mcabbott

README.md

@@ -66,7 +66,7 @@ Flux v0.13 is the latest right now, marked with ☀️; models upgraded to use
 **Vision**
 * MNIST
   * [Simple multi-layer perceptron](vision/mlp_mnist) ☀️ v0.13 +
-  * [Simple ConvNet (LeNet)](vision/conv_mnist) ☀️ v0.13
+  * [Simple ConvNet (LeNet)](vision/conv_mnist) ☀️ v0.13 +
   * [Variational Auto-Encoder](vision/vae_mnist) ☀️ v0.13 +
   * [Deep Convolutional Generative Adversarial Networks](vision/dcgan_mnist) ☀️ v0.13 +
   * [Conditional Deep Convolutional Generative Adversarial Networks](vision/cdcgan_mnist) ☀️ v0.13