#157 add measured_on function to application helper, add nil checking to each measured/collected/observed_on function
#157 add measured_on function to application helper, add nil checking to each measured/collected/observed_on function

osu-cascades/ecotone-web,osu-cascades/ecotone-web,osu-cascades/ecotone-web,osu-cascades/ecotone-web