Add ability to use context sensitive searches in primo

To do a context search on primo view, simply change the primo_views yaml like so.

```yaml
CU:
  redirects:
    - /cooper
  tabs:
    all:
      default_precision: contains
      searches:
        default:
          contains: digital divide
          exact: little prince
          starts_with: global warming
      context-name:
          contains: different search
          exact: different search
          starts_with: different search
```

And add `bobcat_context: context-name` in your config.yml file.