Release v0.0.7

• WekaEstimator (module sklweka.classifiers) now has a custom score method that distinguishes between classification and regression to return the correct score.
• renamed data to X and targets to y, since some sklearn schemes use named arguments
• added dummy argument sample_weight=None to fit, score and fit_predict methods
• fixed: when supplying Classifier or JBObject instead of classname/options, classname/options now get determined automatically
• method to_instance (module: sklweka.dataset) now performs correct missing value check
• method to_nominal_labels (module: sklweka.dataset) generates nicer labels now