Get the unique items from

['nowplaying', 'PBS', 'PBS', 'nowplaying', 'job', 'debate', 'thenandnow']

This can be one of three ways:

1. Order does not matter.

   ['thenandnow', 'debate', 'nowplaying', 'PBS', 'job']

2. Preserve the order. Keep the first unique one.

   ['nowplaying', 'PBS', 'job', 'debate', 'thenandnow']

3. Preserve the order. Keep the last unique one.

   ['PBS', 'nowplaying', 'job', 'debate', 'thenandnow']