Add a template for search list items

In order to customise how search results are shown, I've moved the
main search result template to using a new specific template,
initially a copy of core/generic_list_item.html, but soon to change.
Improve speech search result template for south africa

I've made use of the ancestors of the speech section to show exactly
where the speech being return is (eg: Hansard, etc) and included the
speaker name. I've also made it a bigger and more obvious link by
wrapping the whole matched excerpt in an anchor, rather than just a
little bit.

Some styling to make this look a bit better is still needed, but
hopefully this goes some way towards #1163
Tweak SASS for South African search results

Increasing the spacing between things vertically helps make it clearer
that there are different groups of results.
Merge branch 'master' of ssh://git.mysociety.org/data/git/public/pombola