Frontend: Give boarders to result preview
Frontend: Add tooltips on hover
Frontend: Small fix to tooltips
Frontend: Insert footer
Frontend: Exclude empty synsets from being displayed

Synset only gets displayed, if it contains image clusters or any of its children contain image clusters.
Question: Do we want to display the other cluster terms somewhere?
Frontend: Set results min height

#result.min-height = body.height - navbar.height - footer.height
Frontend: Onclick onto a preview, a modal popup with image clones opens