TraceShape maxPoses doesn't allow you to set maxPoses to 0 (Infinity).

[kauffmanes]

I made a pull request for this, but the CI build failed due to one of your npm modules (https://travis-ci.org/RobotWebTools/ros2djs/jobs/568488362). I don't want to make any changes to your package.json, so I'm including this issue.

Here's the overview:
To set maxPoses to Infinity, you have to pass a 0 to TraceShape, but when setting this.maxPoses in the TraceShape function, it does this: this.maxPoses = options.maxPoses || 100. If I set maxPoses to 0 (meaning I want it to be infinity) the line of code evaluates it to be a falsy value and sets maxPoses to 100 instead. My code just checks to see if it's defined OR it equals 0.