Overhauled system settings and added some configurables

Squashed commit of the following:

commit cfa99be7541288ccadacaea305d8d98251e8a629
Author: Thomas Schank <DrTom@schank.ch>
Date:   Tue Apr 16 12:58:49 2013 +0200

    Replaced wiki_url with support_url

commit 28971240d852b7d3ca9bc94c1dde993d90fc54cf
Author: Thomas Schank <DrTom@schank.ch>
Date:   Tue Apr 16 09:53:53 2013 +0200

    Link footer image to madek.zhdk.ch

commit 314fe7d3c0d3ff98147e3859a04e75233fced3ef
Author: Thomas Schank <DrTom@schank.ch>
Date:   Tue Apr 16 08:48:35 2013 +0200

    Restored wiki settings link

commit 257f15e68220c64513504e35852dc5361f47cac0
Author: Thomas Schank <DrTom@schank.ch>
Date:   Tue Apr 16 08:39:08 2013 +0200

    Removed Rack content_length middle ware test seek after deploy

commit 40562e407c70854d47c2eb7c60f483beb039f23c
Author: Thomas Schank <DrTom@schank.ch>
Date:   Mon Apr 15 16:38:04 2013 +0200

    Always edit settings, never show

commit 13799a4d9d4a06a02bebd7605173206d99e57012
Author: Thomas Schank <DrTom@schank.ch>
Date:   Mon Apr 15 16:32:43 2013 +0200

    Setting and using footer_links

commit 6fcb4b1eb2422496ffff1e6457b280ea47f26278
Author: Thomas Schank <DrTom@schank.ch>
Date:   Mon Apr 15 10:44:19 2013 +0200

    Added logo and brand to application settings

commit bf3b5e4a19281194b21d71b3628c8a32a712bb4d
Author: Thomas Schank <DrTom@schank.ch>
Date:   Fri Apr 12 16:21:34 2013 +0200

    Fixed dropbox creation test feature

commit 1cab8de447b7448de70e867a093749dba4b3b811
Author: Thomas Schank <DrTom@schank.ch>
Date:   Fri Apr 12 16:02:04 2013 +0200

    Fixing some stuff with the dropbox

commit 399976bb808d9c53d11d0bdc155ff3144a3b6527
Author: Thomas Schank <DrTom@schank.ch>
Date:   Fri Apr 12 14:08:00 2013 +0200

    updated personas datbase

commit 5f28ca6d3598e31e1450f4b3cd3616073447bb34
Author: Thomas Schank <DrTom@schank.ch>
Date:   Fri Apr 12 13:34:59 2013 +0200

    Setting title in migration and rather use :each instead of :all in specs

commit d311e925051ef74d15f489dffe8c8866f0c83e16
Author: Thomas Schank <DrTom@schank.ch>
Date:   Fri Apr 12 10:48:19 2013 +0200

    Clened specs

commit 8dc7ae38a3e42a878e15953dea3dab8f3e9492a4
Author: Thomas Schank <DrTom@schank.ch>
Date:   Fri Apr 12 10:20:39 2013 +0200

    Fixed migration when there are no old settings to import

commit 6d5e452ee951d488bd59e3e0f5be6845be93ec08
Author: Thomas Schank <DrTom@schank.ch>
Date:   Fri Apr 12 10:02:16 2013 +0200

    Cleaning up old settings

commit 24ee2712d052eacf5b9cf8a0a42bd931b25fb714
Author: Thomas Schank <DrTom@schank.ch>
Date:   Fri Apr 12 09:20:49 2013 +0200

    Enabled authentication systems in app settings

commit a0ce18975df7fdb14f27632c777b6bed877a19cb
Author: Thomas Schank <DrTom@schank.ch>
Date:   Thu Apr 11 14:43:31 2013 +0200

    nicer form

commit 79dad417844c292fc25d84b34b3e9cc0e58d6133
Author: Thomas Schank <DrTom@schank.ch>
Date:   Thu Apr 11 14:32:36 2013 +0200

    added dropbox settings

commit c8fd3d3427842f760e6cb772e47cccde550e5490
Author: Thomas Schank <DrTom@schank.ch>
Date:   Thu Apr 11 14:27:08 2013 +0200

    Basic edit for set ids

commit 9d0fafe6025e18bc6b9a8e41f560c01d7f22ef30
Author: Thomas Schank <DrTom@schank.ch>
Date:   Thu Apr 11 12:50:58 2013 +0200

    Show settings

commit 02a356c96b9dc8851acb6897cd2219273c5e9a32
Author: Thomas Schank <DrTom@schank.ch>
Date:   Thu Apr 11 12:45:49 2013 +0200

    Use methods missing to simulate old AppSetting behaviour

commit 2efe90f253a3b564a497423416805fdef79ef698
Author: Thomas Schank <DrTom@schank.ch>
Date:   Thu Apr 11 10:59:20 2013 +0200

    Added app_admin settings stuff

commit bc0e0ec865e18ffb968587bb1cb7d702426f4aaf
Author: Thomas Schank <DrTom@schank.ch>
Date:   Thu Apr 11 10:16:21 2013 +0200

    Data migration for app settings

commit 6972dba6ed5a8788e88804323be467174d10e81e
Author: Thomas Schank <DrTom@schank.ch>
Date:   Thu Apr 11 09:54:05 2013 +0200

    Added migration for new madek_settings