Overhaul of thread handling to support blocking functions other than wait

luprex/core/lua/login.lua

@@ -3,6 +3,7 @@ makeclass('login')
 function login.interface(actor, place)
     gui.menu_item("cb_becomeplayer", "Become a Player")
     gui.menu_item("cb_p123", "Print 1, 2, 3")
+    gui.menu_item("cb_p123_nopredict", "Print 1, 2, 3 nopredict")
     end
 
 function login.cb_becomeplayer(actor, place, dialog)
@@ -20,9 +21,21 @@ function login.cb_p123(actor, place, dialog)
     print(3)
     end
 
+function login.cb_p123_nopredict(actor, place, dialog)
+    nopredict()
+    print(1)
+    wait(1)
+    print(2)
+    wait(1)
+    print(3)
+    end
+
 -- this is function documentation for setfoo.
 function setfoo(n)
-    tangible.nopredict()
+    if (n == nil) then 
+        error("setfoo(n) - n must be an integer")
+    end
+    nopredict()
     tangible.actor().inventory.foo = n
     end