message: global_include_test: more slack for timing test
  The macOS travis-ci test quite often fails with:
  DroneLink/core/global_include_test.cpp:27: Failure
  Expected: (seconds_elapsed) < (0.11), actual: 0.11005 vs 0.11
  This is a try to prevent it.
diff: @@ -24,7 +24,7 @@ TEST(GlobalInclude, ElapsedSinceAboutRight)
  double seconds_elapsed = elapsed_since_s(time_before);
  ASSERT_GT(seconds_elapsed, 0.09);
  - ASSERT_LT(seconds_elapsed, 0.11);
  + ASSERT_LT(seconds_elapsed, 0.12); // we need some slack for macOS CI on travis.
  }
  TEST(GlobalInclude, SteadyTimeInFuture)
  