Qt SVG: Not so 1.2 Tiny any more

With this step, we are opening Qt SVG up to support elements beyond SVG Tiny 1.2. This means that we will aim to include useful and common elements from SVG 1.1 and SVG 2.0, if maintenance is reasonably feasible. We will not aim for compliance with these standards but we will keep an eye on feature requests from our users. Further, we are open to contributions of such extensions by the community. So if you miss your favorite SVG element in the list above, fell free to send us some code, preferably on our code review platform.