Periodic table update

Our periodic table component has a few issues:

• Sometimes the selected elements are not synced with the selected filters. This problems is rooted in the fact that the table uses an internal selection state that is parallel to the one stored in <SearchContext> to make the selections more responsive while clicking around. Mentioned also by @josma here
• The rendering performance of the component is quite bad. Rendering the periodic table is the bottleneck in loading the filter menu. Also somehow simply the presence of the periodic table makes e.g. the other widgets respond a bit more slowly (e.g. dragging the view in a scatter plot), even though chrome shows no repaints of the periodic table..? My initial feeling is that the performance problems are caused by the fact that the component is built using <table> and hundreds of <div>s. Replacing this with an SVG-based version might be a good idea.