[MEDIUM] introduce task->nice and boot access to statistics

The run queue scheduler now considers task->nice to queue a task and
to pick a task out of the queue. This makes it possible to boost the
access to statistics (both via HTTP and UNIX socket). The UNIX socket
receives twice as much a boost as the HTTP socket because it is more
sensible.
diff --git a/src/proto_uxst.c b/src/proto_uxst.c
index c4c3d37..6968562 100644
--- a/src/proto_uxst.c
+++ b/src/proto_uxst.c
@@ -447,6 +447,7 @@
 		task_init(t);
 		t->process = l->handler;
 		t->context = s;
+		t->nice = -64;  /* we want to boost priority for local stats */
 
 		s->task = t;
 		s->fe = NULL;