Create new LaserScan angle filter for inverted lasers

[5yler]

The laser_filters package LaserScanAngularBoundsFilter implementation allows filtering between a lower_angle and upper_angle value, but assumes lower_angle < upper_angle.

This doesn't work with the RPLIDAR if rotated 180 degrees, since angle_min = -pi and angle_max = pi and the points we want to keep for the forward facing 180 degrees would lie on the two intervals [-pi, -pi/2] and [pi/2, pi]

Tasks

• [x] implement new scan filter that allows throwing the middle points rather than the two side intervals
• [x] replace launch occurrences of the LaserScanAngularBoundsFilter with the new LaserScanAngleFilter implementation as needed
  • [x] XV LIDAR on the front of Gigatron
  • [x] RPLIDAR on the front of Gigatron (depending on final mounting configuration)

[5yler]

This is done. Some follow-up tasks remain.

[5yler]

I think this is done, the forward facing scan for both LIDARs displays correctly in RViz, and the RPLIDAR scan gives correct outputs in the drive script.