Updated README, improving some of the section code.

public/components/section/Section.jsx

@@ -41,6 +41,7 @@ export default props => {
 import BodySection from './body/BodySection';
 import ClearSection from './layout/ClearSection';
 import ImageSection from './image/ImageSection';
+import BannerImageSection from './image/banner/BannerImageSection';
 import SplitSection, { Split }  from './layout/SplitSection';
 import VideoSection from './video/VideoSection';
 
@@ -48,6 +49,7 @@ export {
   BodySection,
   ClearSection,
   ImageSection,
+  BannerImageSection,
   SplitSection,
   Split,
   VideoSection