message: Split up Heading story into modifier stories
diff: import React from 'react';
  -import { flow } from 'lodash/fp';
  import { storiesOf } from '@storybook/react';
  -import { withNotes } from '@storybook/addon-notes';
  import { withInfo } from '@storybook/addon-info';
  import withTests from '../src/util/withTests';
  import { PlainHeading as Heading } from '../src/components/Heading';
  -import README from '../src/components/Heading/README.md';
  -storiesOf('Headings', module)
  +storiesOf('Heading', module)
  .addDecorator(withTests('Heading'))
  .add(
  - 'Heading',
  - flow(withNotes(README), withInfo())(() => [
  - <Heading key="h1zetta" element="h1" size="zetta">
  + 'Zetta Heading with h1',
  + withInfo()(() => (
  + <Heading element="h1" size="zetta">
  This is a zetta heading with an h1 element
  - </Heading>,
  - <Heading key="h2exa" element="h2" size="exa">
  + </Heading>
  + ))
  + )
  + .add(
  + 'Exa Heading with h2',
  + withInfo()(() => (
  + <Heading element="h2" size="exa">
  This is an exa heading with an h2 element
  - </Heading>,
  - <Heading key="h3peta" element="h3" size="peta">
  + </Heading>
  + ))
  + )
  + .add(
  + 'Peta Heading with h3',
  + withInfo()(() => (
  + <Heading element="h3" size="peta">
  This is a peta heading with an h3 element
  - </Heading>,
  - <Heading key="h4tera" element="h4" size="tera">
  + </Heading>
  + ))
  + )
  + .add(
  + 'Tera Heading with h4',
  + withInfo()(() => (
  + <Heading element="h4" size="tera">
  This is a tera heading with an h4 element
  - </Heading>,
  - <Heading key="h5giga" element="h5" size="giga">
  + </Heading>
  + ))
  + )
  + .add(
  + 'Giga Heading with h5',
  + withInfo()(() => (
  + <Heading element="h5" size="giga">
  This is a giga heading with an h5 element
  - </Heading>,
  - <Heading key="h6mega" element="h6" size="mega">
  + </Heading>
  + ))
  + )
  + .add(
  + 'Meta Heading with h6',
  + withInfo()(() => (
  + <Heading element="h6" size="mega">
  This is a mega heading with an h6 element
  - </Heading>,
  - <Heading key="h6kilo" element="h6" size="kilo">
  + </Heading>
  + ))
  + )
  + .add(
  + 'Kilo Heading with h6',
  + withInfo()(() => (
  + <Heading element="h6" size="kilo">
  This is a kilo heading with an h6 element
  </Heading>
  - ])
  + ))
  );
  