Add os.scandir and os.DirEntry (#424)

Introduced in Python 3.5

stdlib/3/os/__init__.pyi

@@ -105,6 +105,20 @@ WNOHANG = 0  # Unix only
 TMP_MAX = 0  # Undocumented, but used by tempfile
 
 # ----- os classes (structures) -----
+if sys.version_info >= (3, 5):
+    class DirEntry:
+        # This is what the scandir interator yields
+        # The constructor is hidden
+
+        name = ''
+        path = ''
+        def inode(self) -> int: ...
+        def is_dir(self, follow_symlinks: bool = ...) -> bool: ...
+        def is_file(self, follow_symlinks: bool = ...) -> bool: ...
+        def is_symlink(self) -> bool: ...
+        def stat(self) -> stat_result: ...
+
+
 class stat_result:
     # For backward compatibility, the return value of stat() is also
     # accessible as a tuple of at least 10 integers giving the most important
@@ -259,6 +273,11 @@ def renames(old: AnyStr, new: AnyStr) -> None: ...
 if sys.version_info >= (3, 3):
     def replace(src: AnyStr, dst: AnyStr) -> None: ...
 def rmdir(path: AnyStr) -> None: ...
+if sys.version_info >= (3, 5):
+    @overload
+    def scandir(path: str = ...) -> Iterator[DirEntry]: ...
+    @overload
+    def scandir(path: bytes) -> Iterator[DirEntry]: ...
 def stat(path: AnyStr) -> stat_result: ...
 def stat_float_times(newvalue: Union[bool, None] = ...) -> bool: ...
 def statvfs(path: str) -> statvfs_result: ... # Unix only