GitLab

add learning rate to dart (#133)

* add gridsearch example for python sklearn

* reset_learning_rate->reset_parameter

* make callbacks public

* clean python docs

* clean python docs

* add python doc

* add boosting_type to python sklearn

* fix error

Provide a high level Dataset class for easy use.

current problem:
callback order: user-defined in callback parameter -> reset_learning_rate/print_evaluation/record_evaluation/early_stop
user can't insert a callback between last 4 callbacks

solution:
set order variable:
reset_learning_rate = 10
print_evaluation = 10
record_evaluation = 20
early_stop = 30
user-defined = some int
default: according to index in callback parameter list, = index - len(callbacks) (all < 0)

current callback order:
before iter: user-defined -> reset_learning_rate -> user-defined
after iter: user-defined -> print_evaluation -> user-defined -> record_evaluation -> user-defined -> early_stop -> user-defined