Random refactoring of some threejs code

after.js

materialGroups = groupedMaterials.map(function (group) {
	return group.map(function (name) { return namedMaterials[name];  });
});

before.js

for (var g = 0; g < groupedMaterials.length; g++) {
	var arr = [];
	materialGroups.push(arr);
	
	var group = groupedMaterials[g];
	
	// Extract each group member and push to group array
	for (var i in group) {
    	var name = group[i];
    
    	arr.push(namedMaterials[name]);
	}
}