Added Code Syntax parsing to CodeNode

Added code syntax parsing to CodeNode.   The main change was to add parsing after the ``` for synax.

So 
\`\`\`java 
...
\`\`\`

will result in:

&lt;pre&gt;
&lt;code data-code-syntax="java"&gt;
...
&lt;/code&gt;
&lt;/pre&gt;