Split stdlib into Python 2 and 3 versions (#5442)

All new files in stdlib/@python2 are straight copies of the
corresponding files in stdlib.

stdlib/@python2/curses/__init__.pyi

@@ -0,0 +1,15 @@
+from _curses import *  # noqa: F403
+from _curses import _CursesWindow as _CursesWindow
+from typing import Any, Callable, TypeVar
+
+_T = TypeVar("_T")
+
+# available after calling `curses.initscr()`
+LINES: int
+COLS: int
+
+# available after calling `curses.start_color()`
+COLORS: int
+COLOR_PAIRS: int
+
+def wrapper(__func: Callable[..., _T], *arg: Any, **kwds: Any) -> _T: ...

stdlib/@python2/curses/ascii.pyi

@@ -0,0 +1,62 @@
+from typing import List, TypeVar, Union
+
+_CharT = TypeVar("_CharT", str, int)
+
+NUL: int
+SOH: int
+STX: int
+ETX: int
+EOT: int
+ENQ: int
+ACK: int
+BEL: int
+BS: int
+TAB: int
+HT: int
+LF: int
+NL: int
+VT: int
+FF: int
+CR: int
+SO: int
+SI: int
+DLE: int
+DC1: int
+DC2: int
+DC3: int
+DC4: int
+NAK: int
+SYN: int
+ETB: int
+CAN: int
+EM: int
+SUB: int
+ESC: int
+FS: int
+GS: int
+RS: int
+US: int
+SP: int
+DEL: int
+
+controlnames: List[int]
+
+def isalnum(c: Union[str, int]) -> bool: ...
+def isalpha(c: Union[str, int]) -> bool: ...
+def isascii(c: Union[str, int]) -> bool: ...
+def isblank(c: Union[str, int]) -> bool: ...
+def iscntrl(c: Union[str, int]) -> bool: ...
+def isdigit(c: Union[str, int]) -> bool: ...
+def isgraph(c: Union[str, int]) -> bool: ...
+def islower(c: Union[str, int]) -> bool: ...
+def isprint(c: Union[str, int]) -> bool: ...
+def ispunct(c: Union[str, int]) -> bool: ...
+def isspace(c: Union[str, int]) -> bool: ...
+def isupper(c: Union[str, int]) -> bool: ...
+def isxdigit(c: Union[str, int]) -> bool: ...
+def isctrl(c: Union[str, int]) -> bool: ...
+def ismeta(c: Union[str, int]) -> bool: ...
+def ascii(c: _CharT) -> _CharT: ...
+def ctrl(c: _CharT) -> _CharT: ...
+def alt(c: _CharT) -> _CharT: ...
+def unctrl(c: Union[str, int]) -> str: ...

stdlib/@python2/curses/panel.pyi

@@ -0,0 +1,20 @@
+from _curses import _CursesWindow
+
+class _Curses_Panel:  # type is <class '_curses_panel.curses panel'> (note the space in the class name)
+    def above(self) -> _Curses_Panel: ...
+    def below(self) -> _Curses_Panel: ...
+    def bottom(self) -> None: ...
+    def hidden(self) -> bool: ...
+    def hide(self) -> None: ...
+    def move(self, y: int, x: int) -> None: ...
+    def replace(self, win: _CursesWindow) -> None: ...
+    def set_userptr(self, obj: object) -> None: ...
+    def show(self) -> None: ...
+    def top(self) -> None: ...
+    def userptr(self) -> object: ...
+    def window(self) -> _CursesWindow: ...
+
+def bottom_panel() -> _Curses_Panel: ...
+def new_panel(__win: _CursesWindow) -> _Curses_Panel: ...
+def top_panel() -> _Curses_Panel: ...
+def update_panels() -> _Curses_Panel: ...

stdlib/@python2/curses/textpad.pyi

@@ -0,0 +1,11 @@
+from _curses import _CursesWindow
+from typing import Callable, Optional, Union
+
+def rectangle(win: _CursesWindow, uly: int, ulx: int, lry: int, lrx: int) -> None: ...
+
+class Textbox:
+    stripspaces: bool
+    def __init__(self, win: _CursesWindow, insert_mode: bool = ...) -> None: ...
+    def edit(self, validate: Optional[Callable[[int], int]] = ...) -> str: ...
+    def do_command(self, ch: Union[str, int]) -> None: ...
+    def gather(self) -> str: ...