2.7 stub updates (#149)

* Stubgen modules for 2.7

Cookie
email._parseaddr
email.utils
genericpath
linecache
mimetypes
multiprocessing
multiprocessing.process
multiprocessing.util
posixpath
quopri
runpy
weakref
wsgiref.validate

* 2.7/typing.py: add missing __contains__ definition

* 2.7/subprocess.py: make output argument to CalledProcessError optional

Commit f08160bd did the same for py3.

* 2.7/hmac.pyi: add compare_digest

This function was introduced to the 2.7 series in 2.7.7.

* Stubgen 2.7/ssl.pyi

This replaces a nearly-empty handwritten stub.

* Copy constants and other definitions from py3 to py2 ssl.pyi

* 2.7/__future__.pyi: add methods

* 2.7/_weakref.pyi: backport some definitions from 3.x version

* Stubgen 2.7/locale.pyi

Hand-edited to remove declarations that are redundant (and cause
conflicts with) the "from _locale import *" line.

stdlib/2.7/hmac.pyi

@@ -1,6 +1,6 @@
 # Stubs for hmac (Python 2)
 
-from typing import Any
+from typing import Any, AnyStr
 
 class HMAC:
     def update(self, msg: str) -> None: ...
@@ -9,3 +9,5 @@ class HMAC:
     def copy(self) -> HMAC: ...
 
 def new(key: str, msg: str = ..., digestmod: Any = ...) -> HMAC: ...
+
+def compare_digest(a: AnyStr, b: AnyStr) -> bool: ...