Option for lookup local hostname as seen by the IRC server

[Pan7]

Option to disable hostname lookup if DCC or any other p2p service isn't required. No more "Looking up the local hostname as seen by the IRC server " and "Unable to resolve the local hostname as seen by the IRC server: DNS query failed, using previously resolved" ... messages.

[wodim]

Need to bump KVI_NUM_BOOL_OPTIONS

[Pan7]

Maybe it would be better to remove the lookup because IRC servers often change it to protect users.

[ctrlaltca]

The lookup can still be useful to others, so removing it is not convenient. A option already exists to avoid resolving the hostname returned by the server. Look at the "broken bouncer hack" in DCC -> Advanced