Print errors in VolumeMaterialExtractor
Cleanup CreateTetrahedralMesh

* Setting the number of tuples is not enough to reserve memory, one must
Allocate the memory also.
* Print more debug information in Verbose mode
* Disable ReleaseDataFlag as it seems to be an issue for writting the
polydata in Linux.
Fix python error in Workflow when there is no color node in display node
Merge branch 'cleanup-createtetrahedralmesh' into next

* cleanup-createtetrahedralmesh:
  Fix python error in Workflow when there is no color node in display node
  Cleanup CreateTetrahedralMesh
  Print errors in VolumeMaterialExtractor
Allow interaction with the octoherdorn or cylinder in pose mode

So far in pose mode the only way to move the bone was to either click on
the line or the tail. The user should also be able to interact with the
octohedron or the cylinder in pose mode.
Code-wise, the pose mode check was simply remove to allow interaction with
the octohedron or cylinder.
Fix pose mode bug

In pose mode it can happen that the bone currently manipulated and all its
children will disappear. This was caused by the lines used for the rotation
computation being the same, leading to a bad angle (NaN in this case).
The event where the two lines are the same are now simply disregarded.
An assert was added to help for future debugging.
Merge branch 'FixArmatureHandling' into next

* FixArmatureHandling:
  Fix pose mode bug
  Allow interaction with the octoherdorn or cylinder in pose mode