OFString: Add methods for UTF-32.
OFTCPSocket: Set ai_flags.

For connect(), this sets ai_flags to:
AI_NUMERICSERV | AI_ADDRCONFIG

For bind(), this sets ai_flags to:
AI_NUMERICSERV | AI_ADDRCONFIG | AI_PASSIVE
OFTCPSocket: Use getnameinfo with NI_NUMERICSERV.
Update copyright.