FauxPose ILLIXR plugin

Summary

The FauxPose ILLIXR plugin generates "fast_pose" data from a simple mathematical algorithm (circular movement). The intent is for use when debugging other plugins and the developer wants a known pose trajectory without having to configure actual tracking.

The movement is hard-coded to be on the Y=center.y plane, with the X and Z values set to rotate in a circle. The period and amplitude of the movement are have default values (0.5, and 2.0 respectively) that can be changed through environment variables.

Topic details:
-   *Publishes* `pose_position` on `fast_pose` topic.

Usage

The "FauxPose" plugin must be included in the YAML configuration file prior to any rendering plugin (such as debugview or gldemo). Also, no other pose-generating plugin should be included.

An example profiles/fauxpose.yaml configuration file is included as an example.

By default, the "orbit" of the tracked position will be about the point (0.0, 1.5, 0.0), with a default amplitude of " 2.0", and period of "0.5" seconds, with the orientation facing the negative-X direction. The first three of these values can be overridden through environment variables:

- FAUXPOSE_PERIOD=<n>
- FAUXPOSE_AMPLITUDE=<n>
- FAUXPOSE_CENTER=<x,y,z>