[bin] region to weight no need graph
[weight] move compute code in loading
[test] UNKNOWN -> NO_3D_CLASS

UNKNOWN sounds much better to me though,
but we need to update clara, and existing models first.

While here, dont use deprecated enum (bands names are dynamic).
One can use gdal.get_band("name") instead.
[doc] add blender to gdal cheats
[nav_graph] do not connect obstacle
[python] dont crash for trajectory parse error
[python] draw pom/tarck on orthoimage
[tools] disputm w/scale
[python] add tool to draw pom.log on geoimage

TODO cleanup and merge python scripts (in gladysplay)