Move contents of builtins/* to stdlib/*. This simplifies finding stubs.

stdlib/3/resource.pyi

@@ -0,0 +1,13 @@
+# Stubs for resource
+
+# NOTE: These are incomplete!
+
+from typing import Tuple
+
+RLIMIT_CORE = 0
+
+def getrlimit(resource: int) -> Tuple[int, int]: ...
+def setrlimit(resource: int, limits: Tuple[int, int]) -> None: ...
+
+# NOTE: This is an alias of OSError in Python 3.3.
+class error(Exception): ...