[#43122757] application settings

Squashed commit of the following:

commit 092f8d685a26e1362d885c9974cc4372253e6b2e
Author: Franco Sellitto <franco.sellitto@zhdk.ch>
Date:   Mon Aug 5 13:56:33 2013 +0200

    - fixing constants definition in Setting
    - application#load_settings before_filter, where singleton are always required
    - tests

commit b1ade364cf967878d8574bc523868d0902c28885
Author: Franco Sellitto <franco.sellitto@zhdk.ch>
Date:   Wed Jul 31 17:41:37 2013 +0200

    [#43122757] introducing application settings

commit cabdce09d7f8ad19441f1d725bef25002a37d909
Author: Matus Kmit <matus.kmit@zhdk.ch>
Date:   Fri Aug 2 10:41:12 2013 +0200

    Fix CI: Various tests

    Fix CI: Modell.Modellzubehoer deaktivieren

    Fix CI: Benutzer verwalten.Elemente der Benutzeradministration

commit 7f6e073399b14209608abb3c1480b4a89772c5dd
Author: Franco Sellitto <franco.sellitto@zhdk.ch>
Date:   Fri Aug 2 17:31:35 2013 +0200

    defining settings as constants in the Setting class

commit 0f4e0624c91f09aa8a46a6881442bb4c4115ea0d
Author: Franco Sellitto <franco.sellitto@zhdk.ch>
Date:   Fri Aug 2 11:58:25 2013 +0200

    missing migration

commit ee911887482e27f0a66f834022615995633cf437
Author: Franco Sellitto <franco.sellitto@zhdk.ch>
Date:   Wed Jul 31 17:41:37 2013 +0200

    [#43122757] introducing application settings