[docs] Python wrapper doesn't support params in form of list of pairs

[StrikerRUS]

params is only supported in form of dict.
Also, fixed some typos.

[StrikerRUS]

GPU test fails.

Seems it's due to new Boost release:

CMake Warning at /usr/local/share/cmake-3.12/Modules/FindBoost.cmake:847 (message):
  New Boost version may have incorrect or missing dependencies and imported
  targets
Call Stack (most recent call first):
  /usr/local/share/cmake-3.12/Modules/FindBoost.cmake:963 (_Boost_COMPONENT_DEPENDENCIES)
  /usr/local/share/cmake-3.12/Modules/FindBoost.cmake:1622 (_Boost_MISSING_DEPENDENCIES)
  CMakeLists.txt:100 (find_package)


CMake Warning at /usr/local/share/cmake-3.12/Modules/FindBoost.cmake:847 (message):
  New Boost version may have incorrect or missing dependencies and imported
  targets
Call Stack (most recent call first):
  /usr/local/share/cmake-3.12/Modules/FindBoost.cmake:963 (_Boost_COMPONENT_DEPENDENCIES)
  /usr/local/share/cmake-3.12/Modules/FindBoost.cmake:1622 (_Boost_MISSING_DEPENDENCIES)
  CMakeLists.txt:100 (find_package)


-- Boost version: 1.69.0
-- Found the following Boost libraries:
--   filesystem
--   system
-- Configuring done
-- Generating done

Compare with yesterday's master:

-- Boost version: 1.58.0
-- Found the following Boost libraries:
--   filesystem
--   system
-- Configuring done
-- Generating done

@huanzhang12 Can you please take a look?