mv _solver_type_dict to subclass

Before this, you can set loss = "lr", "l1r", "lr2" in LinearSVC to do
logistic regression and linear svr.
clean preparation for fitting

1. combine _transfrom_data and _validate_data to _prepare_fit
2. rely on self.class_weight_ for class weight
Merge branch 'liblinear' into local
fix shape of LinearSVR prediction
Merge branch 'liblinear' into local