module to validate/manipulate IPv6 addresses

 Net::IPv6Addr checks if strings are valid IPv6 addresses, as specified in
 RFC1884, and can convert them into other supported formats including:
 .
  * Preferred form x:x:x:x:x:x:x:x
  * Compressed form with double colon: x::x
  * Mixed IPv4/IPv6 format: x:x:x:x:x:x:d.d.d.d
  * Mixed IPv4/IPv6 with compression: x::x:d.d.d.d
  * Base-85-encoded
  * Big integers
  * Arrays
  * Reverse-address pointer
 .
 When creating/validating an IPv6 address from a given string, Net::IPv6Addr
 will either accept it or throw an exception.