RFR: Adding project explanation

[Marcus Hirt via github.com]

The pull request has been updated with additional changes.

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

Added commits:
 - b77b8906:	Update README.md
			Co-Authored-By: Erik Duveblad <erik.helin at oracle.com>

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

Webrevs:
 - full: https://webrevs.openjdk.java.net/skara/16/webrev.02
 - inc: https://webrevs.openjdk.java.net/skara/16/webrev.01-02

Updated full patch:
https://git.openjdk.java.net/skara/pull/16.diff

Fetch command:
git fetch https://git.openjdk.java.net/skara pull/16/head:pull/16