Add 'Return Mode' to LAS output from MBMAX64, if the LIDAR sends it to us.

The Velodyne LIDARs output the following information to HYSWEEP:

The Velodyne VLP-16 ‘Point Return’ information consists of the following:

A. Laser Return values (distances)

B. Calibrated Reflectivity values (Intensities)

C. Azimuth values

D. Time Stamp

E. Return Mode (Strongest, Last, Dual)

Customer would like the 1.E. Return Mode information stored in LAS files that are generated from MBMAX64, as they often use other processing programs, that can utilize this information for data filtering.

Velodyne driver would have to be modified to record this information. The above data is provided to the driver, currently, just not recorded in the TOP message.