Implement defineProperty to efficiently handle data changes when Proxy is not supported

[ultimate-tester]

Proxy is a relatively new API and not supported by Internet Explorer.
defineProperty, on the other hand, is supported by Internet Explorer and the same behaviour can be achieved with this method. Therefore it would be wise to use defineProperty as a fallback to Proxy.

Open questions so far:

• What will happen if the object already contains a property, will the get/set methods still be called?