RFR: Adding project explanation

[Marcus Hirt via github.com]

..as suggested in the Twitter discussion. :)

----------------

Commits:
 - 4578553b:	Adding project explanation

Pull request:
http://git.openjdk.java.net/skara/pull/16

Webrev:
https://openjdk.github.io/cr/skara/16/webrev.00

Patch:
http://git.openjdk.java.net/skara/pull/16.diff

Fetch command:
git fetch https://github.com/openjdk/skara.git 4578553b:pr/16