Get rid of double spaces in UK postcode and PL street name

PL:
* Faker::Address.street_name => "ul.  Filipek" # two spaces

UK:
* Faker::Address.postcode => "Z5  5JL" # also two spaces

Now there is only one space.
Get rid of double space in Spanish street names
Merge pull request #130 from sgabler/remove-double-spaces

Get rid of double spaces in UK postcode and PL street name