New features on visitation bar graph

[sgwinder]

From Sarah Lange: "It would be nice to be able to select a year and display the monthly bar graph for that year rather than just seeing the average of entire time series (or better yet select multiples and be able to compare). Also can you imprint the time series on bar graphs (2012-2018) for the avg monthly visits onto the scale so that if the image is exported/screenshot, etc. that information stays with it?"