fix(Holder): Named default export of Holder.tsx

Closes danilowoz#131 Closes danilowoz#132

Author: danilowoz

src/index.ts

@@ -1,5 +1,5 @@
 import ContentLoader from './Holder'
-import { IContentLoaderProps } from './interface'
+export { IContentLoaderProps } from './interface'
 
 export { default as Facebook } from './stylized/FacebookStyle'
 export { default as Instagram } from './stylized/InstagramStyle'
@@ -8,4 +8,3 @@ export { default as List } from './stylized/ListStyle'
 export { default as BulletList } from './stylized/BulletListStyle'
 
 export default ContentLoader
-export { IContentLoaderProps }