Displacement eval fixes, AK_Camo deprecated

- Custom Object Normal, Axis Mask, Paintable Gabor and PolysurfaceCurvature will no longer error in displacement
- PolysurfaceCurvature will return black when used in displacement
- Gabor will not error but still seems to be prone to crashing Mari when using displacement

- AK_Camo was deprecated. It has been replaced by AK_CamoTwo,