[#53380683] fix categories on borrow start

Squashed commit of the following:

commit 4cf12e436160da90f66c3a5cf6e91dea1a7b009c
Author: Franco Sellitto <franco.sellitto@zhdk.ch>
Date:   Mon Jul 22 13:17:29 2013 +0200

    [#52717037] [#53385393] [#53050507]

    Conflicts:
    	Gemfile
    	app/views/borrow/orders/unsubmitted_order.html.haml
    	db/structure.sql
    	features/borrow/bestelluebersicht.feature
    	features/borrow/timeoutpage.feature
    	features/borrow/verfuegbarkeit.feature
    	features/step_definitions/borrow/bestelluebersicht_steps.rb
    	locale/de_CH/leihs.po
    	locale/leihs.pot

commit a450d5a86058d5720e515340815b8a1e670d47fa
Author: Sebastian Pape <email@sebastianpape.com>
Date:   Mon Jul 22 10:32:20 2013 +0200

    [#52973127] fix borrow search not showing

    Squashed commit of the following:

    commit 717ad0316b1c2496366a16b2a7cca2afd8577c32
    Author: Sebastian Pape <email@sebastianpape.com>
    Date:   Fri Jul 19 11:43:48 2013 +0200

        [FIX CI] modellliste.feature

    commit 2896b64f20c2c0983f409801ef580e24c260fe80
    Author: Sebastian Pape <email@sebastianpape.com>
    Date:   Fri Jul 19 14:02:16 2013 +0200

        integration tests for not seeing models you dont have permissions for

    commit a031bce8df5a3baf9bf9a92ca813892dde39b230
    Author: Sebastian Pape <email@sebastianpape.com>
    Date:   Thu Jul 18 15:39:51 2013 +0200

        fix seeing models i dont have access for

    commit 7665936d8ea741e2801b715e9dd25d224ba13ff9
    Author: Franco Sellitto <franco.sellitto@zhdk.ch>
    Date:   Fri Jul 12 11:13:13 2013 +0200

        introducing user.models.borrowable joining partitions_with_generals sql view

commit 41c98a3b8bd44c399b073b9fa07abe257913cdfb
Author: Matus Kmit <matus.kmit@zhdk.ch>
Date:   Thu Jul 18 11:45:07 2013 +0200

    Finished test and bug fix

commit 69f9561006c990e99d6a447216012188fc723df4
Author: Matus Kmit <matus.kmit@zhdk.ch>
Date:   Wed Jul 17 18:34:40 2013 +0200

    Fix categories tests

commit 6a618ecc00b6a0e411f6ac99a4972f88eb5b9390
Author: Matus Kmit <matus.kmit@zhdk.ch>
Date:   Wed Jul 17 15:55:42 2013 +0200

    Borrow root categories filtering WIP