Add stdlib/3/tokenize.pyi (#151)

Mostly stubgen, with open() added by hand because stubgen somehow
doesn't see it.

stdlib/3/tokenize.pyi

@@ -0,0 +1,99 @@
+# Stubs for tokenize (Python 3.5)
+#
+# NOTE: This dynamically typed stub was automatically generated by stubgen.
+
+from typing import Any, Union, TextIO
+from builtins import open as _builtin_open
+from token import *
+
+COMMENT = ... # type: Any
+NL = ... # type: Any
+ENCODING = ... # type: Any
+
+class TokenInfo:
+    @property
+    def exact_type(self): ...
+
+class TokenError(Exception): ...
+class StopTokenizing(Exception): ...
+
+class Untokenizer:
+    tokens = ... # type: Any
+    prev_row = ... # type: Any
+    prev_col = ... # type: Any
+    encoding = ... # type: Any
+    def __init__(self): ...
+    def add_whitespace(self, start): ...
+    def untokenize(self, iterable): ...
+    def compat(self, token, iterable): ...
+
+def untokenize(iterable): ...
+def detect_encoding(readline): ...
+def tokenize(readline): ...
+
+def open(filename: Union[str, bytes, int]) -> TextIO: ...
+
+# Names in __all__ with no definition:
+#   AMPER
+#   AMPEREQUAL
+#   ASYNC
+#   AT
+#   ATEQUAL
+#   AWAIT
+#   CIRCUMFLEX
+#   CIRCUMFLEXEQUAL
+#   COLON
+#   COMMA
+#   DEDENT
+#   DOT
+#   DOUBLESLASH
+#   DOUBLESLASHEQUAL
+#   DOUBLESTAR
+#   DOUBLESTAREQUAL
+#   ELLIPSIS
+#   ENDMARKER
+#   EQEQUAL
+#   EQUAL
+#   ERRORTOKEN
+#   GREATER
+#   GREATEREQUAL
+#   INDENT
+#   ISEOF
+#   ISNONTERMINAL
+#   ISTERMINAL
+#   LBRACE
+#   LEFTSHIFT
+#   LEFTSHIFTEQUAL
+#   LESS
+#   LESSEQUAL
+#   LPAR
+#   LSQB
+#   MINEQUAL
+#   MINUS
+#   NAME
+#   NEWLINE
+#   NOTEQUAL
+#   NT_OFFSET
+#   NUMBER
+#   N_TOKENS
+#   OP
+#   PERCENT
+#   PERCENTEQUAL
+#   PLUS
+#   PLUSEQUAL
+#   RARROW
+#   RBRACE
+#   RIGHTSHIFT
+#   RIGHTSHIFTEQUAL
+#   RPAR
+#   RSQB
+#   SEMI
+#   SLASH
+#   SLASHEQUAL
+#   STAR
+#   STAREQUAL
+#   STRING
+#   TILDE
+#   VBAR
+#   VBAREQUAL
+#   tok_name