test: update range slider mocks

- the new rangePlot routine generates much sharper lines
plotly · etpinard · Oct 11, 2016 · Oct 6, 2016 · Oct 6, 2016 · Oct 6, 2016
commit 1b627a532c27f80731d88dd011e9aee9c9e03261
diff --git a/test/image/baselines/range_slider.png b/test/image/baselines/range_slider.png
diff --git a/test/image/baselines/range_slider_initial_expanded.png b/test/image/baselines/range_slider_initial_expanded.png
diff --git a/test/image/baselines/range_slider_initial_valid.png b/test/image/baselines/range_slider_initial_valid.png