GraphViewer: The CommunityNodes are now able to expand and collapse themselfes.
GraphViewer: The communitynode now renders the size next to it
GraphViewer: Each communityNode now creats its own ForceLayouter
GraphViewer: Added a wrapper around the MutationObserver for Cross-Browser support
Merge branch 'devel' of github.com:triAGENS/ArangoDB into devel