National trunk prefix

[direc85]

Test cases for #76 and #68 which seem to be the same issue.

[direc85]

Condensed test results:

it3 at src/formatter.rs:466:48:
 called `Result::unwrap_err()` on an `Ok` value

it2 at src/formatter.rs:451:9:
  left: "+39 391 2312312"
 right: "+39 12312312"

ru2 at src/formatter.rs:420:9:
  left: "+78005553535"
 right: "+7005553535"

be1 at src/formatter.rs:386:9:
  left: "+375800111111"
 right: "+3750111111"

ru1 at src/formatter.rs:409:9:
  left: "+78005553535"
 right: "+7005553535"

Which interestingly means:

• parser::parse(Some(country::RU), "+78005553535") passes
• parser::parse(None, "+78005553535") fails

[paulll]

Which interestingly means:

• parser::parse(Some(country::RU), "+78005553535") passes
• parser::parse(None, "+78005553535") fails

parser::parse(Some(country::RU), "+78005553535") is ru1 test case
parser::parse(None, "+78005553535") is ru3 which passes