Toggle location

Created a toggle button after searching to allow users to opt to show their location or not.

Asana task:
https://app.asana.com/0/8548956980512/16035494530316/f
I'm sorry for suggesting `btn-lg`.
Change the class attribute to the following for a better appearance:
```html
class="btn btn-default"
```
See http://getbootstrap.com/components/ for reference.