Remove dependency on the CZPicker pod

The latest commit on the [CZPicker repo](https://github.com/chenzeyu/CZPicker) was in 2016. We depend on this pod to show the pop-up selector views when a user requests a match.

**Possible Solutions**
* Find a more actively maintained replacement pod
* Re-write the sections handled by CZPicker ourself.

Note: Need not be solved right away.