[fix bug 1009018] Responsify HTML tables on Reps

Foundation have a responsive `<table>` plugin that I think could make data-heavy pages on Reps work much nicer on small screens. 

This PR adds responsive tables to `/dashboard`, `/reports` and `/voting` at mobile break-point sizes, which are probably the main pages where this could be of benefit.

The responsive tables work by using an overflow-scrolling area on table data, instead of trying to squeeze everything to the width of the page.