evadeDomainFilter with elasticY causes lines to be clipped

[kum-deepak]

It seems elasticY considers only the visible part of the chart to calculate minimum/maximum domain values. When combined with evadeDomainFilter lines may get outside the chart area.

See the attached screen grab from http://dc-js.github.io/dc.js/examples/range-series.html

[gordonwoodhull]

This is a result of #1376 - we do want to use only the visible part of the graph to determine min / max Y. We don't want to squish the display just because there is some really large point way off the canvas.

But I think it's a little more complicated than what that PR implemented. We need to consider points just barely outside the X domain.

Technically we'd want to intersect the lines with the vertical lines at the domain start and end, and min / max over those intersection points as well as the points within the domain. But it would probably be good enough to include one point on each side which is just outside the X domain.

Interestingly, this is related to the correct solution for the problem which evadeDomainFilter fixes stupidly. #949 also suggests including just one point outside the domain.

[kum-deepak]

Maybe we can go onto this one after completing the composite brushing.