Added dump_model() to simple_example.py (#911)
Added dump_model() to simple_example.py (#911)

The example page state that "simple_example.py" should feature an example of json dump, but that was missing.
microsoft/LightGBM,olofer/LightGBM,microsoft/LightGBM,Laurae2/LightGBM,olofer/LightGBM,henry0312/LightGBM,olofer/LightGBM,olofer/LightGBM,henry0312/LightGBM,Laurae2/LightGBM,wxchan/LightGBM,wxchan/LightGBM,Allardvm/LightGBM,Laurae2/LightGBM,henry0312/LightGBM,microsoft/LightGBM,Laurae2/LightGBM,microsoft/LightGBM,henry0312/LightGBM,Allardvm/LightGBM,Laurae2/LightGBM,henry0312/LightGBM,olofer/LightGBM,wxchan/LightGBM,Allardvm/LightGBM,Allardvm/LightGBM,Allardvm/LightGBM,wxchan/LightGBM,wxchan/LightGBM,microsoft/LightGBM