[Feature Request] Option to only show trace of last N samples in XY plot.

[ckgt]

Thanks for contributing to PlotJuggler. You are great! Really!

Problem description

I have a bunch of XY data I plot and plot juggler shows a trace over all XY data. This can make for some crazy XY plots if the data have some noise. It would be nice to be able to only show a trace of the last N samples or T minutes from the time on the time slider. Maybe even changing the opacity or color of each sample based on it's age would be super helpful visually.

Steps to reproduce (important)

• Create XY plot for long timeseries with noisy data
• Giant spaghetti monster shows up

[akruzliak]

This would be a very important feature addition, since controller input is often modelled in the way of XY plot and when I want to validate correct body velocities of robot against controller inputs it's impossible to see.