fix #86 original image is replaced by image with same name
add logging
throw exception when it tries to overwrite exists file
change exception name for local storage conflict, delete logger comment from services xml
Merge branch 'develop' into bugfix/86
added logger to service definition
fix test clean up
Merge branch 'bugfix/86' of git://github.com/sulu-cmf/SuluMediaBundle into bugfix/86
Merge pull request #87 from sulu-cmf/bugfix/86

[BUGFIX] original image is replaced