Squashed commit of the following:

commit 5abcc280d6f8c460d1fe90e9478d89116cdce5d7
Author: Holger Brand <H.Brand@gsi.de>
Date:   Thu May 8 09:57:23 2014 +0200

    Reference MainDev branch

commit 4b1acdfbaf021593298816641ca83b0e5db1f24e
Author: Alexander Kessler <alexander.kessler@uni-jena.de>
Date:   Fri Jan 31 14:56:05 2014 +0100

    short description about GIT project structure in README.txt is added.

commit 62660259e6bba81c51ce8cd5f71f74f5077043c2
Author: Holger Brand <H.Brand@gsi.de>
Date:   Mon Jul 8 11:27:02 2013 +0200

    Add user requirements specification.

commit 3c4330a190db03f0383cf887d357f78de7d74ef2
Author: Holger Brand <H.Brand@gsi.de>
Date:   Thu Jun 13 16:11:39 2013 +0200

    Extend first line with more keywords to be better found on GitHub.
Prepare for release.