GitLab

* added plot_split_value_histogram function

* updated init module

* added plot split value histogram example

* added plot_split_value_histogram to notebook

* added test

* fixed pylint

* updated API docs

* fixed grammar

* set y ticks to int value in more sufficient way

* updated gitignore

* updated tree index with cat feature

* removed excess import

* added tests for plotting trees in Python

* refined module_INSTALLED mechanism

* added note about that create_tree_digraph is better than plot_tree

* added missed description of plot_example in python_guide folder and fixed consistency for packages naming

* more reliable OS detection

* fixed grammar

* made pylint happy

* python-package: add graphviz.Digraph parameters

* examples: add a plottig example with graphviz

* fix tree index in print

* add plot metrics

* move 'raise Exception' to check_not_tuple_of_2_elements

* rename 'plot_metrics' to 'plot_metric'

* fix misleading message/docs

* change 'Metrics' in title to 'Metric'

* fix misleading comment

* add plot tree

* add docs

* add example

* add test

* fix test

* fix decision type

* add show_info

* use feature name if available

* add plot importance

* add plot example