Charts demo using SVG instead of div modification

Following the tutorial changed to use SVG graphics instead of div
modification as previously. Also added new necessary CSS rules.
Extracted JS into its own static directory

Javascript to render svg elements now extracted into static/js/  Makes
debugging easier thanks to the reloads being done by the static file
server.
Switching example to load data instead

Loading data served in tsv file requies changes to javascript.  Not
entirely working yet.
Updating the CSS to make the letters grey to debug
Fixing bugs in page SVG chart display

Wasn't returning the value for the length of the rects.
Changed the number color back to white so they're visible.
Basic vertical bar charts working