Re-organize directory structure (#4971)

See discussion in #2491

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

stdlib/@python2/subprocess.pyi

@@ -0,0 +1,115 @@
+from typing import IO, Any, Callable, Generic, List, Mapping, Optional, Sequence, Text, Tuple, TypeVar, Union
+
+_FILE = Union[None, int, IO[Any]]
+_TXT = Union[bytes, Text]
+_CMD = Union[_TXT, Sequence[_TXT]]
+_ENV = Union[Mapping[bytes, _TXT], Mapping[Text, _TXT]]
+
+# Same args as Popen.__init__
+def call(
+    args: _CMD,
+    bufsize: int = ...,
+    executable: _TXT = ...,
+    stdin: _FILE = ...,
+    stdout: _FILE = ...,
+    stderr: _FILE = ...,
+    preexec_fn: Callable[[], Any] = ...,
+    close_fds: bool = ...,
+    shell: bool = ...,
+    cwd: Optional[_TXT] = ...,
+    env: Optional[_ENV] = ...,
+    universal_newlines: bool = ...,
+    startupinfo: Any = ...,
+    creationflags: int = ...,
+) -> int: ...
+def check_call(
+    args: _CMD,
+    bufsize: int = ...,
+    executable: _TXT = ...,
+    stdin: _FILE = ...,
+    stdout: _FILE = ...,
+    stderr: _FILE = ...,
+    preexec_fn: Callable[[], Any] = ...,
+    close_fds: bool = ...,
+    shell: bool = ...,
+    cwd: Optional[_TXT] = ...,
+    env: Optional[_ENV] = ...,
+    universal_newlines: bool = ...,
+    startupinfo: Any = ...,
+    creationflags: int = ...,
+) -> int: ...
+
+# Same args as Popen.__init__ except for stdout
+def check_output(
+    args: _CMD,
+    bufsize: int = ...,
+    executable: _TXT = ...,
+    stdin: _FILE = ...,
+    stderr: _FILE = ...,
+    preexec_fn: Callable[[], Any] = ...,
+    close_fds: bool = ...,
+    shell: bool = ...,
+    cwd: Optional[_TXT] = ...,
+    env: Optional[_ENV] = ...,
+    universal_newlines: bool = ...,
+    startupinfo: Any = ...,
+    creationflags: int = ...,
+) -> bytes: ...
+
+PIPE: int
+STDOUT: int
+
+class CalledProcessError(Exception):
+    returncode: int
+    # morally: _CMD
+    cmd: Any
+    # morally: Optional[bytes]
+    output: bytes
+    def __init__(self, returncode: int, cmd: _CMD, output: Optional[bytes] = ...) -> None: ...
+
+# We use a dummy type variable used to make Popen generic like it is in python 3
+_T = TypeVar("_T", bound=bytes)
+
+class Popen(Generic[_T]):
+    stdin: Optional[IO[bytes]]
+    stdout: Optional[IO[bytes]]
+    stderr: Optional[IO[bytes]]
+    pid: int
+    returncode: int
+    def __new__(
+        cls,
+        args: _CMD,
+        bufsize: int = ...,
+        executable: Optional[_TXT] = ...,
+        stdin: Optional[_FILE] = ...,
+        stdout: Optional[_FILE] = ...,
+        stderr: Optional[_FILE] = ...,
+        preexec_fn: Optional[Callable[[], Any]] = ...,
+        close_fds: bool = ...,
+        shell: bool = ...,
+        cwd: Optional[_TXT] = ...,
+        env: Optional[_ENV] = ...,
+        universal_newlines: bool = ...,
+        startupinfo: Optional[Any] = ...,
+        creationflags: int = ...,
+    ) -> Popen[bytes]: ...
+    def poll(self) -> Optional[int]: ...
+    def wait(self) -> int: ...
+    # morally: -> Tuple[Optional[bytes], Optional[bytes]]
+    def communicate(self, input: Optional[_TXT] = ...) -> Tuple[bytes, bytes]: ...
+    def send_signal(self, signal: int) -> None: ...
+    def terminate(self) -> None: ...
+    def kill(self) -> None: ...
+
+def list2cmdline(seq: Sequence[str]) -> str: ...  # undocumented
+
+# Windows-only: STARTUPINFO etc.
+
+STD_INPUT_HANDLE: Any
+STD_OUTPUT_HANDLE: Any
+STD_ERROR_HANDLE: Any
+SW_HIDE: Any
+STARTF_USESTDHANDLES: Any
+STARTF_USESHOWWINDOW: Any
+CREATE_NEW_CONSOLE: Any
+CREATE_NEW_PROCESS_GROUP: Any