ui/js: upgrade PDF js lib and integration

Squashed commit of the following:

commit c454c179029a26609b083955058027db6d2deb97
Author: Jonasz Grochowski <tensaioni@gmail.com>
Date:   Wed Aug 20 11:23:02 2014 +0200

    Add missing files

commit 9e239519cf506c072e6d528edd1d57f12fb7843f
Author: Jonasz Grochowski <tensaioni@gmail.com>
Date:   Mon Aug 11 08:24:32 2014 +0200

    Preliminary pdf.js update
Admin interface: extract admins from admin group
fixes
another fix
rspec test fix