v0.5

• Adding a new OptimizerPolicy class allowing to have Phase-based learning rate policies. The two following learning policies are also provided:
  • "Super-Convergence: Very Fast Training of Neural Networks Using Large Learning Rates", Leslie N. Smith, Nicholay Topin, https://arxiv.org/abs/1708.07120
  • "SGDR: Stochastic Gradient Descent with Warm Restarts", Ilya Loshchilov, Frank Hutter, https://arxiv.org/abs/1608.0398
• Adding of "bin_acc" metric for binary classification in addition to the "accuracy" metric".
• Adding "time" in callbacks' logs.
• Various refactoring and small bug fixes.