adding tooltips for links; need to finalize the styling
adding tooltips for links; need to finalize the styling


Former-commit-id: cbc39567d0824d577c1d6033a9df35b18736bd45
uwgraphics/CooccurViewer,uwgraphics/CooccurViewer,uwgraphics/CooccurViewer,uwgraphics/CooccurViewer