Removed Apple specific volume rendering setting
Removed Apple specific volume rendering setting

This was forcing ray cast (needed with OpenGL1) and causing many
issues with large volumes on the Mac in tomviz.

OpenChemistry/tomviz,mathturtle/tomviz,OpenChemistry/tomviz,mathturtle/tomviz,mathturtle/tomviz,cryos/tomviz,cjh1/tomviz,OpenChemistry/tomviz,thewtex/tomviz,thewtex/tomviz,cryos/tomviz,cjh1/tomviz,thewtex/tomviz,OpenChemistry/tomviz,cryos/tomviz,cjh1/tomviz