Issues/1109b nigeria pu search views

Closes #1109, builds on PR #1116 

On the normal search page there is now some text...

![_foo_____search____shineyoureye](https://f.cloud.github.com/assets/187630/1789890/92e1cf08-6965-11e3-8a89-a84341d791cf.png)

...that leads you to the new poll unit number search...

![search_for_places_using_your_poll_unit_number____shineyoureye](https://f.cloud.github.com/assets/187630/1789897/b9877716-6965-11e3-86aa-7cb1fbec0266.png)

...where you can search by poll unit number...

![la_2_4_5_results____shineyoureye-2](https://f.cloud.github.com/assets/187630/1789903/e135fa8a-6965-11e3-8eda-1570a700f4cf.png)

If you search for a short poll unit number you get more results (just 'LA' is the state Lagos):

![la_results____shineyoureye](https://f.cloud.github.com/assets/187630/1789911/07af5044-6966-11e3-81b0-0314a574b181.png)