Fix IDT error # bug, add debug helper, continue debugging spawn_thread crash

The crash occurs after the newly-created stack is accessed, suggesting
that there is some bug in the paging code.
diff --git a/src/kernel/main.c b/src/kernel/main.c
index b61efda..17a54d7 100644
--- a/src/kernel/main.c
+++ b/src/kernel/main.c
@@ -65,7 +65,7 @@
 
 	asm("sti");
 
-	// init_tasks();
+	init_tasks();
 	init_sync();
 
 	pci_init();