RadarVolumeStyle is not integrated in main development

[FransKnibbe]

RadarVolumeStyle was contributed by Toshiba, as the example web page shows. However, the code was not fully integrated in the main development branch. This can be demonstrated by changing the aforementioned example page. Replacing the referenced file x3dom-full.js (which has version 1.7.1-dev) with the current version of x3dom-full.js (1.7.2 at the time of writing this) will make the two sliders (cross section plane and threshold) stop working.

Another aspect of the issue is that the description of the RadarVolumeStyle node in the documentation differs greatly from the way it is used in the example page.

[andreasplesch]

c46e603#diff-50edde9131a502e8155c639b5339c3d0 for some reason removed all that functionality.