add compileall stubs to 3 and add types to the ones in 2 (#1023)

* add compileall stubs to 3 and add types to the ones in 2

Didn't merge the stubs because all functions have additional parameters since 3.2,
so there would be no shared code between 2 and 3.

* add comment

stdlib/2/compileall.pyi

@@ -1,7 +1,10 @@
 # Stubs for compileall (Python 2)
-#
-# NOTE: This dynamically typed stub was automatically generated by stubgen.
 
-def compile_dir(dir, maxlevels=..., ddir=..., force=..., rx=..., quiet=...): ...
-def compile_file(fullname, ddir=..., force=..., rx=..., quiet=...): ...
-def compile_path(skip_curdir=..., maxlevels=..., force=..., quiet=...): ...
+from typing import Optional, Pattern, Union
+
+_Path = Union[str, bytes]
+
+# fx can be any object with a 'search' method; once we have Protocols we can change the type
+def compile_dir(dir: _Path, maxlevels: int = ..., ddir: _Path = ..., force: bool = ..., rx: Optional[Pattern] = ..., quiet: int = ...) -> None: ...
+def compile_file(fullname: _Path, ddir: _Path = ..., force: bool = ..., rx: Optional[Pattern] = ..., quiet: int = ...) -> None: ...
+def compile_path(skip_curdir: bool = ..., maxlevels: int = ..., force: bool = ..., quiet: int = ...) -> None: ...