Changes 'Place' by 'Country'

Just changes "Place" by "Country" in City names and in Postal code options.

The Administrative regions option should be reviewed also in the near future but the two changed texts are critical.

The reason of this change is basically that, currently, the way our internal geocoder works only understands Countries in the old "Place" selector. This was provoking a lot of confusion.

Please, @saleiva (this is what I told you in the retreat) and @xavijam, review.