Added strict voxelization option also in BoostMaskGenerateMaskVoxelListThread.

Summary: Merge branch 'T24990-voxelizerToolFails' (bug report of VoxelizerTool by DKFZ user)

Test Plan: VoxelizerTool voxelizes the requesting structures now with strict option

Reviewers: wieset

Reviewed By: wieset

Differential Revision: https://phabricator.mitk.org/D146