Core documentation

Documented all the elements in the core module. Everything works as expected so far.

docs/doc-fragments/docFragments.js

@@ -1,6 +1,10 @@
 var gettingStarted = require('./gettingStarted');
 var commonTextualElements = require('./commonTextualElements');
+var headings = require('./headings');
+var lists = require('./lists');
+var images = require('./images');
+var codeAndQuotations = require('./codeAndQuotations');
 
 module.exports = [
-  gettingStarted, commonTextualElements
+  gettingStarted, commonTextualElements, images, lists, codeAndQuotations
 ]