added image selection content type
added image selection tests
added image selection service and template
renamed images => media
implemented media-selection simple ui
added datagrid options
implemented get overlay data
implemented get media by ids (api)
fixed ui
added collections header
fixed add tab style
build css files
implemented render medias
added docs
implemented js integration
added display option behaviour
Merge branch 'develop' of git://github.com/sulu-cmf/SuluMediaBundle into feature/image-selection

Conflicts:
	Resources/public/scss/main.scss
fixed direction => displayOption
fixed images preview bug
fixed import