GitLab

* add @property to sklearn interface

* add deprecated; fix binary_metric

* add gridsearch example for python sklearn

* reset_learning_rate->reset_parameter

* make callbacks public

* add feature importances in python; add pandas support

* solve best_iteration issue

1. merge python-package
2. add dump model to json
3. fix bugs
4. clean code with pylint
5. update python examples