Dummy thread improvements (#1309)

* dummy_thread improvements

- Complete the Python 3 stub
- Add a Python 2 stub. They're close enough that they should go into 2and3, but
  the module name changed so we can't do that.

* fix my bugs

stdlib/2/dummy_thread.pyi

@@ -0,0 +1,22 @@
+from mypy_extensions import NoReturn
+from typing import Any, Callable, Dict, Optional, Tuple
+
+class error(Exception):
+    def __init__(self, *args: Any) -> None: ...
+
+def start_new_thread(function: Callable[..., Any], args: Tuple[Any, ...], kwargs: Dict[str, Any] = ...) -> None: ...
+def exit() -> NoReturn: ...
+def get_ident() -> int: ...
+def allocate_lock() -> LockType: ...
+def stack_size(size: Optional[int] = ...) -> int: ...
+
+class LockType(object):
+    locked_status: bool
+    def __init__(self) -> None: ...
+    def acquire(self, waitflag: Optional[bool] = ...) -> bool: ...
+    def __enter__(self, waitflag: Optional[bool] = ...) -> bool: ...
+    def __exit__(self, typ: Any, val: Any, tb: Any) -> None: ...
+    def release(self) -> bool: ...
+    def locked(self) -> bool: ...
+
+def interrupt_main() -> None: ...

stdlib/3/_dummy_thread.pyi

@@ -1,11 +1,22 @@
-# Stubs for _dummy_thread
+from mypy_extensions import NoReturn
+from typing import Any, Callable, Dict, Optional, Tuple
 
-# NOTE: These are incomplete!
-
-from typing import Any
-
-class LockType:
-    def acquire(self) -> None: ...
-    def release(self) -> None: ...
+TIMEOUT_MAX: int
+error = RuntimeError
 
+def start_new_thread(function: Callable[..., Any], args: Tuple[Any, ...], kwargs: Dict[str, Any] = ...) -> None: ...
+def exit() -> NoReturn: ...
+def get_ident() -> int: ...
 def allocate_lock() -> LockType: ...
+def stack_size(size: Optional[int] = ...) -> int: ...
+
+class LockType(object):
+    locked_status: bool
+    def __init__(self) -> None: ...
+    def acquire(self, waitflag: Optional[bool] = ..., timeout: int = ...) -> bool: ...
+    def __enter__(self, waitflag: Optional[bool] = ..., timeout: int = ...) -> bool: ...
+    def __exit__(self, typ: Any, val: Any, tb: Any) -> None: ...
+    def release(self) -> bool: ...
+    def locked(self) -> bool: ...
+
+def interrupt_main() -> None: ...