Merge branch 'hotfix/content-type'
updated composer
Merge branch 'develop'

Conflicts:
	composer.json
removed serializer
added type check
fixed testcases
cleaned to array function
Merge pull request #66 from sulu-cmf/hotfix/remove-serializer

[HOTFIX] Removed serializer to serialize media container and added type check in serialization
Merge branch 'master' of git://github.com/sulu-cmf/SuluMediaBundle into develop
updated version numbers