add id incrementing when duplicate material ids are found in scene
add id incrementing when duplicate material ids are found in scene

Kesshi/Babylon.js,NicolasBuecher/Babylon.js,BabylonJS/Babylon.js,Kesshi/Babylon.js,RaananW/Babylon.js,NicolasBuecher/Babylon.js,sebavan/Babylon.js,BabylonJS/Babylon.js,Kesshi/Babylon.js,sebavan/Babylon.js,RaananW/Babylon.js,BabylonJS/Babylon.js,sebavan/Babylon.js,NicolasBuecher/Babylon.js,RaananW/Babylon.js