[IMP] change webclient structure: remove table

[IMP] change webclient structure: remove table

This is a small change if measured in lines of code, but is a large
change: it removes the table structure from the web client and use divs
instead.  It will likely break a lot of things (some css selectors
will not work), but it should simplify our lives in the future:
closer to being responsive, easier layout computations for the browsers
(and hopefully less discrepencies between the results), simpler html, ...