visual customisation feedback

[missinglink]

I've been playing around with doing some zany visual customisation which highlighted some minor issues with the templating/css vars.

None of this is urgent to fix, I'm just writing it down here so I don't forget ;)

• currently there is no way of completely disabling the placeholder text, a workaround is to use a single space " "
• when using custom 'row' templates the <li> no longer has the result-item and result-item-active classes, this makes it difficult/impossible to style the full width/height background-color of each row. [edit] this was my fault
• allow implementing white-space: nowrap; overflow: hidden; with optional text-overflow: ellipsis;, this is not possible by default, it can be achieved with row templates but requires nesting an additional <span> otherwise the icon width throws off the ellipsis calc. It would be even better if this didn't require using the private API