Quickplot scale should really be a scale bar

[andrewd]

Since you never quite know what sort of scaling the user may have their browser print settings set to, the scale shown for Quick Plot really needs to be a scale bar, not just a number.

Currently, all you see is something like "1:2500". But if the user is printing that shunk down or blown up, that scale will be incorrect (and they'll never know it). A bar is the only fool-proof way to know for sure what the scale actually is.