More NVIDIA-IndeX-plug-in 2.3 fixes
- Fixed random disspearing of irregular volumes in PV-Server.
- Fixed broken tile rendering.
- Gradient kernel cleanup.
Backport: release
Cc: @utkarsh.ayachit @ben.boeckel
Edited by Ben Boeckel
Backport: release
Cc: @utkarsh.ayachit @ben.boeckel