Object.defineProperty not working with older Safari Versions

Hi,

I had a problem with Safari on iOS 6.1.3.

The if check

`if (!("classList" in document.createElement("_")) || document.createElementNS && !("classList" in document.createElementNS("http://www.w3.org/2000/svg", "g")))`

resolves correctly in true and the script comes later to

`try {
objCtr.defineProperty(elemCtrProto, classListProp, classListPropDesc);`

This is a problem in old Safari Versions, because it is not working on DOM Objects. So there is no error but toggle or add will not work with the additional parameters.

I found a working solution for myself by adding

```
if ("document" in self) {
var setPropOnDOM = true;

// Detect if we can define properties on DOM Objects
try {
Object.defineProperty(document.createElement("_"), "classList", {
"get": function() {}
});
} catch (e) { //Old Safari versions will break at this point
setPropOnDOM = false;
}

// Full polyfill for browsers with no classList support
// Including IE < Edge missing SVGElement.classList
if (setPropOnDOM && (!("classList" in document.createElement("_")) || document.createElementNS && !("classList" in document.createElementNS("http://www.w3.org/2000/svg", "g")))) {
```

Old Safaris will resolve in the catch block and then go on with partial support which is then working like expected. I will finish it next week and come back with a clean and fully response when my unit tests are green in all browsers (including old IE, Safari and so on).