Added comment about future gdcm.
Added comment about future gdcm.

chrisidefix/devide,zhangfangyan/devide,fvpolpeta/devide,nagyistoce/devide,nagyistoce/devide,chrisidefix/devide,zhangfangyan/devide,ivoflipse/devide,fvpolpeta/devide,ivoflipse/devide