README.md: Do not refer to SciJava as a "fork"

Yes, it is a GitHub fork, but not a diverging fork in that the SciJava
releases are simply cut from the latest master branch, with no patches.

The main reason for the "fork" now is as a place to put release tags.
README.md: add another working example

Thanks to Matt Gumbley of DevZendo.org for the reference!