Learning paths - updated markdown JAR and removed old SB placeholders

Hi Rich,

Since www-ldn runs on Java 1.6, I had to rebuild the markdown converter JAR using 1.6 compiler options. 

I removed the dos equis learning path and imported learning paths 01 and 02 based on master. You can use the KB admin portlet from Site Admin > Content to import updates using the ZIP file built from running 'ant dist' from learning-paths.

Enjoy!
Jim