message: gimbal_device_tester: switch to C++17 as well
diff: cmake_minimum_required(VERSION 2.8.12)
  +set(CMAKE_CXX_STANDARD 17)
  +set(CMAKE_CXX_STANDARD_REQUIRED ON)
  +
  project(gimbal_device_tester)
  if(NOT MSVC)
  - add_definitions("-std=c++11 -Wall -Wextra ")
  + add_definitions("-Wall -Wextra ")
  # This warning is triggered by the MAVLink includes.
  add_definitions("-Wno-address-of-packed-member")
  else()
  - add_definitions("-std=c++11 -WX -W2")
  + add_definitions("-WX -W2")
  endif()
  find_package(MAVSDK REQUIRED)
  