Report "Created by XYZ" as an author assertion

[pombredanne]

For instance the SVG in https://thenounproject.com/ (e.g. https://thenounproject.com/term/down-direction/1225009/ ) contains such a statement

[pombredanne]

There is of course a risk of false positives such as with "Created by IntelliJ IDEA"

[mjherzog]

Sounds like this will require research to avoid a slew of false positives.