Fix capitalisation of CardinalDirection.abbreviation
Fix capitalisation of CardinalDirection.abbreviation

`CardinalDirection.abbreviation` relied on the capitalisation of the raw
string value to work correctly. Since lowercasing the enum cases, this
has been broken. We are now using lowercase identifiers in Swift, but
the previous capitalisation for the raw values.

andreamazz/Tropos,faimin/Tropos,faimin/Tropos,thoughtbot/Tropos,faimin/Tropos,thoughtbot/Tropos,andreamazz/Tropos,thoughtbot/Tropos,andreamazz/Tropos