Make changes to rootOfCurrentDocumentFragment and viewportElement propagate to children.
Merge pull request #239 from dgileadi/propagate-parent-change

Make changes to rootOfCurrentDocumentFragment and viewportElement propagate to children.
Merge branch '2.x' of https://github.com/SVGKit/SVGKit into 2.x

# Via David Gileadi (1) and adamgit (1)
* '2.x' of https://github.com/SVGKit/SVGKit:
  Make changes to rootOfCurrentDocumentFragment and viewportElement propagate to children.