Converts a UTF-8 unicode string to a punycode ACE string.
== Example
SimpleIdn.to_ascii("møllerriis.com")
=> "xn--mllerriis-l8a.com"
Converts a punycode ACE string to a UTF-8 unicode string.
== Example
SimpleIdn.to_unicode("xn--mllerriis-l8a.com")
=> "møllerriis.com"