Fix and clean VRML importer code.

Whole code has been cleaned and "modernized".
Several crashes were fixed and an exception mechanism has been
setup to avoid some crashes on file read error - but a lot of other
check should be perform to make it reliable!
Some VRML files do not print the face end marker (-1) for the last
face. This behaviour was not supported before. It is now.
Another fix is that Material properties are more inherited from
previously read nodes.
Add a parameter to specify the resolution for Cone, Sphere
and Cylinder shape sources - default value is 12.

Change-Id: Ica830d9dad9cb707389a6a679b382b32e01bc270
Merge topic 'fix_vrml_importer' into master

565c1b81 Fix and clean VRML importer code.