Upgrade to Mypy 0.470. Add colorama stub. Fix identation.

test/stubs/colorama.pyi

@@ -0,0 +1,6 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+from typing import Optional
+
+def init(autoreset: bool = False, convert: Optional[bool] = None, strip: Optional[bool] = None, wrap: bool = True) -> None: ...
+