Highlight line chart series on legend entry hover or click

[jseppi]

Great suggestion from Tim Whiteaker at CRWR:

Problem: Lines can be hidden underneath other lines when the data values are similar. For example, in the statewide view, the line for mining is obscured under the livestock line:

This happens in lots of other views, so a general solution is needed. Tim proposed that when a user hovers (or maybe clicks) on a legend item or the associated chart data table row, that the associated line in the chart could be temporarily brought to the front of all the other lines, and that all the other lines could have their hues subdued or grayed.