Stub: asyncore.pyi (#498)

* Stub: asyncore.pyi

I can't really test this stub since I don't use this module. I believe it's not far from the real thing.

It's based on the source code and not on the documentation.

https://hg.python.org/cpython/file/default/Lib/asyncore.py

* Option ->Optional

* add hint to count, remove addr

* make read/write explicit functions

* add synchat.pyi, move to 2and3

* change sys.version_info test

* try reversing the syntax

stdlib/2and3/asynchat.pyi

@@ -0,0 +1,41 @@
+from typing import Union, Tuple, Sequence
+from abc import abstractmethod
+
+import asyncore
+import socket
+
+class simple_producer:
+    def __init__(self, data: str, buffer_size: int = ...) -> None: ...
+    def more(self) -> str: ...
+
+class async_chat (asyncore.dispatcher):
+    ac_in_buffer_size = ...  # type: int
+    ac_out_buffer_size = ...  # type: int
+    def __init__(self, sock: socket.socket = None, map: asyncore._maptype = None) -> None: ...
+
+    @abstractmethod
+    def collect_incoming_data(self, data: str) -> None: ...
+    @abstractmethod
+    def found_terminator(self) -> None: ...
+    def set_terminator(self, term: Union[str, int, None]) -> None: ...
+    def get_terminator(self) -> Union[str, int, None]: ...
+    def handle_read(self) -> None: ...
+    def handle_write(self) -> None: ...
+    def handle_close(self) -> None: ...
+    def push(self, data: str) -> None: ...
+    def push_with_producer(self, producer: simple_producer) -> None: ...
+    def readable(self) -> bool: ...
+    def writable(self) -> bool: ...
+    def close_when_done(self) -> None: ...
+    def initiate_send(self) -> None: ...
+    def discard_buffers(self) -> None: ...
+
+import sys
+if sys.version_info < (3, 0, 0):
+    class fifo:
+        def __init__(self, list: Sequence[Union[str, simple_producer]] = ...) -> None: ...
+        def __len__(self) -> int: ...
+        def is_empty(self) -> bool: ...
+        def first(self) -> str: ...
+        def push(self, data: Union[str, simple_producer]) -> None: ...
+        def pop(self) -> Tuple[int, str]: ...