Move Fade to its own component

Fixed todolist strikethrough styling with nested lists

app/components/Fade/Fade.js

@@ -0,0 +1,9 @@
+// @flow
+import styled from 'styled-components';
+import { fadeIn } from 'shared/styles/animations';
+
+const Fade = styled.span`
+  animation: ${fadeIn} ${props => props.timing || '250ms'} ease-in-out;
+`;
+
+export default Fade;