Tutorial intro files, header IDs, and check-intros task improvement

Hi Rich,

The are the changes I committed in order to build the tutorials ZIP file and import it onto www-ldn. It's up there at https://www-ldn.liferay.com/develop/tutorials :+1: 

These are preliminary intros, for the most part. There are still plenty of tutorials that I'm in the midst of reviewing, but it least this import gets us on "the board".

Ready to merge. Thanks!
Jim