Merge pull request BrainJS#311 from BrainJS/rnn-time-step-cross-validate

Rnn time step cross validate

Author: robertleeplummerjr

README.md

@@ -295,14 +295,20 @@ With multiple networks you can train in parallel like this:
 const crossValidate = new brain.CrossValidate(brain.NeuralNetwork, networkOptions);
 crossValidate.train(data, trainingOptions, k); //note k (or KFolds) is optional
 const json = crossValidate.toJSON(); // all stats in json as well as neural networks
-const net = crossValidate.toNeuralNetwork();
+const net = crossValidate.toNeuralNetwork(); // get top performing net out of `crossValidate`
 
 
 // optionally later
 const json = crossValidate.toJSON();
 const net = crossValidate.fromJSON(json);
 ```
 
+Use `CrossValidate` with these classes:
+* `brain.NeuralNetwork`
+* `brain.RNNTimeStep`
+* `brain.LSTMTimeStep`
+* `brain.GRUTimeStep`
+
 An example of using cross validate can be found in [examples/cross-validate.js](examples/cross-validate.js)
 
 ### Train Stream