builtins: have the number types derive from the numbers ABCs

This makes e.g. this work:

    from decimal import Decimal
    from numbers import Real

    x: Real = 1.2
    x = Decimal('1.2')

Author: bluetech

stdlib/2/__builtin__.pyi

@@ -11,6 +11,7 @@ from typing import (
 )
 from abc import abstractmethod, ABCMeta
 from ast import mod, AST
+from numbers import Complex, Integral, Real
 from types import TracebackType, CodeType
 import sys
 
@@ -127,7 +128,7 @@ class super(object):
         @overload
         def __init__(self, t: Any) -> None: ...
 
-class int:
+class int(Integral):
     @overload
     def __init__(self, x: Union[Text, bytes, SupportsInt] = ...) -> None: ...
     @overload
@@ -208,7 +209,7 @@ class int:
         def __nonzero__(self) -> bool: ...
     def __index__(self) -> int: ...
 
-class float:
+class float(Real):
     def __init__(self, x: Union[SupportsFloat, Text, bytes, bytearray] = ...) -> None: ...
     def as_integer_ratio(self) -> Tuple[int, int]: ...
     def hex(self) -> str: ...
@@ -271,7 +272,7 @@ class float:
     else:
         def __nonzero__(self) -> bool: ...
 
-class complex:
+class complex(Complex):
     @overload
     def __init__(self, re: float = ..., im: float = ...) -> None: ...
     @overload

stdlib/2and3/builtins.pyi

@@ -11,6 +11,7 @@ from typing import (
 )
 from abc import abstractmethod, ABCMeta
 from ast import mod, AST
+from numbers import Complex, Integral, Real
 from types import TracebackType, CodeType
 import sys
 
@@ -127,7 +128,7 @@ class super(object):
         @overload
         def __init__(self, t: Any) -> None: ...
 
-class int:
+class int(Integral):
     @overload
     def __init__(self, x: Union[Text, bytes, SupportsInt] = ...) -> None: ...
     @overload
@@ -208,7 +209,7 @@ class int:
         def __nonzero__(self) -> bool: ...
     def __index__(self) -> int: ...
 
-class float:
+class float(Real):
     def __init__(self, x: Union[SupportsFloat, Text, bytes, bytearray] = ...) -> None: ...
     def as_integer_ratio(self) -> Tuple[int, int]: ...
     def hex(self) -> str: ...
@@ -271,7 +272,7 @@ class float:
     else:
         def __nonzero__(self) -> bool: ...
 
-class complex:
+class complex(Complex):
     @overload
     def __init__(self, re: float = ..., im: float = ...) -> None: ...
     @overload