Override SearchView for SA

We need to group search results by model type, using a custom view this
should be possible by overriding `extra_context` on the view and
providing extra querysets for the discrete models we want results for.
Haystack views are not like Django views

It seems that the haystack views don't have an `as_view` method, so we
just treat it like a regular class instead.
Search for people and organisations separately in SA

As per the wireframes the results for people and organisations are
expected to be less, so we need to do separate queries for each of them
so we can still display them ordered by importance. Solution partly
inspired by this post on the django-haystack list [1]

> The only way to keep relevancy &
> group by model is either to run many queries (one per model - usually
> performant thanks to query caching) or to run the query and
> post-process the results, regrouping them as you go.

[1] https://groups.google.com/forum/#!msg/django-haystack/MWFU8mBKIMk/d4kAqYGGIvYJ
Override the South Africa search template

Because we're showing results in separate sections (see previous commit)
we need to take control of the html for it. This is a first pass at the
working html.
Fix bug with missing query

If there is no query then we don't need to add the extra context data
for person and organisation searches.
Add tests for south africa custom search view
Override the whole template for the search page

As we're changing lots of this layout it's simpler to have it all in one
place under the south africa app.
Copy templates into SA app for easier customisation
Make the "no results" text specific to result type

Rather than repeating the same text 3 times on the page if there are no
results.
Exclude constituency offices from south africa place index

This allows excluding an index in general.yml so that you can override
it in the country app, however this seems sub-optimal, as it requires a
specific config to be in place for the country app to work properly.
Hopefully this can be fixed when #829 is tackled.
Merge branch 'master' into search-results-page

Conflicts:
	pombola/south_africa/tests.py
	pombola/south_africa/views.py
fixed logo size bug in webkit
tweaked markup on speech item list for search results display
tweaked markup on organisation item list for search results display
changed markup as part of redesign, ticket #731
styled search results page
styled search results page
recompiled source CSS
Fix position of endif in ZA search results template

Because the </div> was outside the if block, it was always getting
rendered, which broke the html when the starting <div> wasn't present.
Merge branch 'master' into search-results-page

Conflicts:
	pombola/south_africa/urls.py
	pombola/south_africa/views.py