Admin meta_terms feature

Squashed commit of the following:

commit b805776fccd123f46e8e0d94f0a0e3b8eabb07bb
Author: Michał Podlecki <m.podlecki@op.pl>
Date:   Mon Mar 17 11:14:44 2014 +0100

    handle Symbol as an argument

commit 11fd205f5bb3bd474fe2b332060fb879791d09df
Merge: 82dc649 42737f4
Author: Thomas Schank <DrTom@schank.ch>
Date:   Mon Mar 17 10:07:41 2014 +0100

    Merge branch 'ts_merging' of github.com:zhdk/madek into ts_merging

commit 82dc64990926ede9714baef6aba8ea54efc58c09
Author: Thomas Schank <DrTom@schank.ch>
Date:   Mon Mar 17 10:07:10 2014 +0100

    modified:   db/structure.sql

commit 709227526e334cc6643bcc10257b883567e740a9
Author: Thomas Schank <DrTom@schank.ch>
Date:   Mon Mar 17 10:06:09 2014 +0100

    Run migration on personas

commit 42737f49a4734357a7dd08d7e0eb9637f86f9975
Author: Michał Podlecki <m.podlecki@op.pl>
Date:   Mon Mar 17 10:00:11 2014 +0100

    remove problematic test

commit 876933a872b52c1c8731a4ac80bd6e67b2c56886
Author: Michael Podlecki <m.podlecki@op.pl>
Date:   Mon Mar 17 09:45:15 2014 +0100

    Merged meta-terms feature

    Conflicts:
    	app/controllers/app_admin/meta_terms_controller.rb
    	app/models/meta_term.rb
    	features/admin_meta_terms.feature

commit baf14bf86b0c8b0e9c71400bce6eb5bc851f7f5e
Author: Michael Podlecki <m.podlecki@op.pl>
Date:   Mon Mar 17 09:37:39 2014 +0100

    Finalized admin meta_terms

    improvments and test for sorting