ACL handling, part II.
Media entities do not need an url attribute - this is generated from id.
* Permission Handling
* Group Handling, Part I.
removed useless gitattributes file
Merge branch 'master' into mediaresource

Conflicts:
	src/main/java/at/ait/dme/yuma/server/config/Config.java
	src/main/java/at/ait/dme/yuma/server/db/entities/MediaEntity.java
	src/main/resources/WEB-INF/applicationContext.xml