Cannot decode domain in uppercase

[abcdmitry]

Library doesn't parse encoded domain in uppercase like XN--D1ABBGF6AIIY.XN--P1AI
However domains in uppercase form are mentioned in many places including IANA domains list http://data.iana.org/TLD/tlds-alpha-by-domain.txt

I think uppercased domains should be treated as valid as well

[abcdmitry]

I have investigated php native idn_to_utf8 function - it works with uppercase domains.
So I've created pull request #17 with necessary fix for the handling of uppercase encoded domains

[renan]

Fixed by #17.