Remove duplicate places from each person on the organisation detail page

Each person entry on an organisation detail page lists the places
that that person is associated with via currently active positions.
This wouldn't remove any redundancy, so you'd see a list like:

  "Western Cape  Western Cape  Western Cape  Western Cape"

This commit changes the behaviour so that only a unique places are
shown.  Fixes #1247.
ZA: order search results to that speeches go from newest to oldest

Fixes #1251. Relying on the ordering of django_ct happening to be
helpful isn't robust in general, but is an easy way to get the
required behaviour for launch of South Africa.
Merge branch 'master' into staging-auto-deployed