Hidden Test Set and Testing Server

One of the biggest limitations of the original MoleculeNet was that there was no hidden test set. This means that many of the papers that have used MoleculeNet datasets test their methods on subset of the datasets and it's very hard to do an apples-to-apples comparisons of different methods. The next generation of MoleculeNet should features a common benchmark challenge with a hidden test set that can be used to evaluate models proposed by different research groups on a fair playing field.