Admin interface: contexs improvements

    - display media sets related to a context
    - show if a context is (not) active in scope of a media set
    - links to ui media sets
Improve MetaTerms in the admin interface

    - alphabetical order adjustments
    - meta terms ordering type as a select input
    - merging meta terms improvements

Squashed commit of the following:

commit 9265ed01c50f0748c1daf675788ba241dfb097f1
Author: Michał Podlecki <m.podlecki@op.pl>
Date:   Mon Jun 30 15:38:00 2014 +0200

    Merged commits:
Break some lines
Update ci tasks