(svn r5594) Be more strict what's allowed to be built in a hangar: if the airport can't handle planes/helicopters don't present and disallow building planes/helicopters - the latter case wasn't covered yet.
Also remove an error message about building aircraft which can't be triggered by a normal client

echo "Setting dedicated network server settings..."
# empty the server password
server_pw = "*"
server_name = "My example dedicated gameserver"