Re-organize directory structure (#4971)

See discussion in #2491

Co-authored-by: Ivan Levkivskyi <ilevkivskyi@dropbox.com>

stdlib/@python2/thread.pyi

@@ -0,0 +1,27 @@
+from typing import Any, Callable
+
+def _count() -> int: ...
+
+class error(Exception): ...
+
+class LockType:
+    def acquire(self, waitflag: int = ...) -> bool: ...
+    def acquire_lock(self, waitflag: int = ...) -> bool: ...
+    def release(self) -> None: ...
+    def release_lock(self) -> None: ...
+    def locked(self) -> bool: ...
+    def locked_lock(self) -> bool: ...
+    def __enter__(self) -> LockType: ...
+    def __exit__(self, typ: Any, value: Any, traceback: Any) -> None: ...
+
+class _local(object): ...
+class _localdummy(object): ...
+
+def start_new(function: Callable[..., Any], args: Any, kwargs: Any = ...) -> int: ...
+def start_new_thread(function: Callable[..., Any], args: Any, kwargs: Any = ...) -> int: ...
+def interrupt_main() -> None: ...
+def exit() -> None: ...
+def exit_thread() -> Any: ...
+def allocate_lock() -> LockType: ...
+def get_ident() -> int: ...
+def stack_size(size: int = ...) -> int: ...