Made the cluster graph wider

This way there are no conflicts for people with sufficiently wide screens. If one uses a small screen it is obvious that one can scroll to see the full graph, but by default the preview will not give conflicts.
Implemented a zoom event on force and collapsible

Now dragging and zooming works! Hence, you can zoom out while keeping the preview, legend and options at a legible size. It should be checked for large graphs whether the parameter of zoomExtent is good enough, but otherwise this feature is awesome squared.
Added a loading message in tag preview

Of course, locally this is barely visible, but it is worth to have this on the actual server I think.
Fixed PHP warning in tag view

This array should be by reference, hence we need to give it a name.
Adding favicon to the graphs
Increased width of the controls

On certain graphs this was not wide enough.
Explain zooming / moving around
Again increased width of controls
Remove tooltips from cluster view

The problem is that it is really difficult to calculate the actual position of the node: the rotation is not visible in the callback data... This is the easiest solution, and as the cluster graph is "stable" and light the preview is what you want anyway.