Update VTK to latest master.

Change-Id: I3237c72a9b45dadb9778ad8a06463ca7d00507af
Merge topic 'update_vtk_master'

2680607 Update VTK to latest master.
Update version to 4.1.0-RC1

Change-Id: I9a5bbd4993ecb36032bb2e5c45bdf3bcae0c732b
Merge topic 'update_version_to_4.1.0-RC1'

ea7294d Update version to 4.1.0-RC1