Add streaming JSON-LOG support. Requires UnrealIRCd 6.1.0+

Add streaming JSON-LOG support. Requires UnrealIRCd 6.1.0+
(post-rc1 git)

Example:

$rpc->log()->subscribe(Array("!debug","all"));
while(1)
{
    echo "Waiting...\n";
    $res = $rpc->eventloop();
    var_export($res);
    echo "\n";
}

$rpc->eventloop() will return NULL if there is no activity
for 10 seconds, so it is not entirely blocking. You can safely
re-run $rpc->eventloop(); if return value === NULL.