Add stubs for pytools

MANIFEST.in

+recursive-include pytato *.pyi

pytato/stubs/pytools.pyi

+# FIXME: Should be in pytools
+from typing import TypeVar, Iterable, Optional
+
+T = TypeVar("T")
+
+def memoize_method(f: T) -> T: ...
+def is_single_valued(it: Iterable[T]) -> bool: ...
+
+class UniqueNameGenerator:
+    def __init__(self, existing_names: Optional[Iterable[str]], forced_prefix: str=""): ...
+    def __call__(self, based_on: str = "") -> str: ...

run-mypy.sh

 #! /bin/bash
 
+export MYPYPATH=$MYPYPATH:pytato/stubs/
 mypy --strict pytato

setup.cfg

@@ -19,7 +19,3 @@ ignore_missing_imports = True
 
 [mypy-pyopencl]
 ignore_missing_imports = True
-
-[mypy-pytools]
-ignore_missing_imports = True
-