Remove dependency on kdelibs4support

It was use for two things:
 * Getting the name of a country from the country code
 * Getting the flag of a country from the country code

The second part wasn't working since the country code is in capital
letters and the flags kdelibs4support installs are in lowercase, so I
have just removed it, given the use is super minor and there's no bug
about it

The first part i've just used the new KCountry class