add new article api resource, fix api image updating, add behat tests
Adds system preferences to template context

It's now possible to use
  $gimme->getSystemPreference(preferenceName, defaultValue)
in the templates. For preference names the machine names should be
used. The default value will be returned if the preferences it not
set.
updated translation resources
Merge pull request #902 from m038/CS-5584_master

Adds system preferences to template context
updated translation resources
add docblocs, add behat tests to travis, smaller fixes
Merge branch 'master' of https://github.com/sourcefabric/Newscoop into new_article_resource

Conflicts:
	newscoop/library/Newscoop/Installer/Services/DatabaseService.php
adjust sample article type
fix sample article type query
fix travis behat command
add placehoders for behat steps and support actions
Merge branch 'master' of https://github.com/sourcefabric/Newscoop into topics
merge fix