Normal computation times

[tabernig]

Computing times for normal are observed to be 10x to 20x slower than those observed in CloudCompare when using the same radii. In addition, but not consistently reproducible: Sometimes when running the normal computation, the algorithm initially uses all available CPU cores. However, after approximately 5 seconds, the process appears to use fewer cores (5/32). Data and code to reproduce the error: https://heibox.uni-heidelberg.de/d/2be30400bc364148989f/