Double check that we actually have array values

Hey Elliot! Love ACF and this add-on. I noticed that when you have a post or whatever that doesn't have a location you get an undefined offset notice. This just provides a check to make sure we should be returning anything.

Thanks!

Hat tip to my friend @MZAWeb :)
Merge pull request #5 from ryanurban/patch-2

Double check that we actually have array values