[build] make miniflowVR build optional (default OFF)
[build] make miniflowVR build optional (default OFF)

Anatoscope/sofa,hdeling/sofa,Anatoscope/sofa,Anatoscope/sofa,FabienPean/sofa,FabienPean/sofa,Anatoscope/sofa,hdeling/sofa,Anatoscope/sofa,hdeling/sofa,Anatoscope/sofa,Anatoscope/sofa,FabienPean/sofa,Anatoscope/sofa,FabienPean/sofa,hdeling/sofa,FabienPean/sofa,hdeling/sofa,FabienPean/sofa,hdeling/sofa,FabienPean/sofa,FabienPean/sofa,hdeling/sofa,hdeling/sofa,FabienPean/sofa,hdeling/sofa,Anatoscope/sofa,FabienPean/sofa,hdeling/sofa