Feature #663

Updated by pospelov about 6 years ago

* if color of MaterialProperty is changed from the editor, this change is propagated to only selected layer, others show previous color
* if Material is deleted from MaterialEditor, Layers and Particles still show old MaterialProperty
* Put check for correct values of RefractiveIndex's delta, beta in MaterialEditor (it is String for the moment)
* after opening existing project, the MaterialEditor doesn't remember the order of materials