LightGBM

[python] added option to install python-package with mpi version and possibility to pass CMake options (#1034)

* fixed hierarchy of installation guide sections; made installation with proto support more verbose

* added option to install with protobuf support to python package

* fixed pylint

* added option to install MPI version to python package

* added tests for python-package installation with options --proto and --mpi

* hotfix

* removed unnecessary note from docs

* removed unnecessary line from travis script

* reverted proto

* Revert "reverted proto"

This reverts commit 5203448bb90a13844cf330527ca971eabb45a4a8.

* reverted protobuf from python-package

* added options for cmake in python-package

* fixed typos

* fixed options readability

* reworked installation logging

* fixed docs according to review comments

* fixed pylint

* fixed space in log path