GitLab

* various minor style, docs and cpplint improvements

* fixed typo in warning

* fix recently added cpplint errors

* move note for params upper in description for consistency

* Update metadata.cpp

* add version for training set, for efficiently update label/weight/... during training.

* Update lgb.Booster.R

* warning for init_score in save_binary

fix #2639

* Update metadata.cpp

* added info into docs
Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* avoid nan and inf in weight/label/init_score

* use prefix increment

* added all necessary includes - fixed build/include_what_you_use error

* fixed the order of includes (build/include_order)

* decode error description

* added break line char in log massages

* Read and write datsets from hdfs.
* Only enabled when cmake is run with -DUSE_HDFS:BOOL=TRUE
* Introduces VirtualFile(Reader|Writer) to asbtract VFS differences

* finish R's c_api

* clean code

* fix sizeof pointer in 32bit system.

* add predictor class

* add Dataset class

* format code

* add booster

* add type check for expose function

* add a simple callback

* add all callbacks

* finish the basic training logic

* update docs

* add an simple training interface

* add basic test

* adapt the changes in c_api

* add test for Dataset

* add test for custom obj/eval functions

* fix python test

* fix bug in metadata init

* fix R CMD check

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

* RAII for utils, application and c_api(partical)

* raii for class in include folder

* raii for application and boosting

* raii for dataset and dataset loader

* raii for dense bin and parser

* RAII refactor for almost all classes

* RAII for c_api

* clean code

* refine repeated code

* Decouple the "sigmoid" between objective and boosting.

* change std::vector<bool> back to std::vector<char> due to concurrence problem

* slight reduce some memory cost

Packages that parse LightGBM’s logs will require minor changes to
parsing logic to work correctly.

support init_score for multiclass classification (#62)