UnIndexed picking fix
UnIndexed picking fix

Support picking for instance of unIndexed mesh,

(Hopefully a fix, PG throws odd error without a empty setter function, https://playground.babylonjs.com/indexStable.html#8QNBES#6)

PG's; Left mesh is indexed sphere, Center mesh is original unIndexed, right mesh is instance. (see console)
With; https://playground.babylonjs.com/indexStable.html#8QNBES#8
Without; https://playground.babylonjs.com/indexStable.html#8QNBES#7
jbousquie/Babylon.js,Kesshi/Babylon.js,jbousquie/Babylon.js,BabylonJS/Babylon.js,BabylonJS/Babylon.js,NicolasBuecher/Babylon.js,Kesshi/Babylon.js,sebavan/Babylon.js,RaananW/Babylon.js,jbousquie/Babylon.js,BabylonJS/Babylon.js,RaananW/Babylon.js,sebavan/Babylon.js,RaananW/Babylon.js,sebavan/Babylon.js,NicolasBuecher/Babylon.js,NicolasBuecher/Babylon.js,Kesshi/Babylon.js