Add support for the United Kingdom (gbr) phone formats

The UK has a fairly complex phone number formatting system which required
a number of special case regexes for splitting.
Merge branch 'united-kingdom' of https://github.com/gordlea/front.phone into united-kingdom

* 'united-kingdom' of https://github.com/gordlea/front.phone:
  Add support for the United Kingdom (gbr) phone formats

Conflicts:
	spec/getPhoneInternational-spec.coffee
	spec/validate-spec.coffee
	src/countries/gbr.coffee