LSTM API about ml5-library

[cvalenzuela]

The LSTM examples 1 and 2 are now implementing this approach:

var lstm = new p5ml.LSTMGenerator('./models/lstm/shakespear/')
let data = {
  seed: 'the queen',
  temperature: 0.5,
  length: 40
}
lstm.generate(data, function(result){
  console.log(result.generated)
});

I also removed the ES6 examples in favor of just ES3 to keep it as simple as possible.

Next step is to update the /training to reflect this changes

[shiffman]

I went through these examples and did a little clean-up, everything looks great! I'm going to close this issue and file two new ones for some small-ish things (including updating "training").