Bug: OptArg values

[schneider-mathias]

When defining range based arguments, e.g.
parser.opt_range('--neurons', default=50, type=int, tunable=True, low=100, high=800, nb_samples=10)
calculated values are not correct. In this case only min and max will be used for hyperparameter optimization instead of the requested 10 parameters which is caused by missing assignment of the member variable (line 372).

Furthermore if log_base parameter is set, only a single value is determined causing an exception in __flatten_params (argparse_hopt.py, line 339). As a fix add nb_samples as argument for np.random.uniform fucntion call (line 379).