Softmax + Categorical Crossentropy

I fixed the activation+loss function, you can't select it directly, it automaticly uses it if it can. I also fixed one-hot generator. Still haven't tested the activation + loss nor any other backward function. I'll do that when I get to the optimizers which is next.

include/neural_network/activation/activation_relu.hpp

@@ -70,6 +70,16 @@ struct activation_relu : public layer{
      */
 	~activation_relu() = default;
 
+    /**
+     * @brief get_type function for layer
+     *
+     * @returns the layer type
+     * 
+     */
+    layer_type get_type() const override {
+        return layer_type::activation_relu;
+    }
+
     /**
      * @brief Forward function for layer
      *