Added latex source syntax_tutorial.tex for syntax_tutorial.pdf
Renamed syntax tutorial filenames
Merge pull request #66 from JonathanWatkins/master

Added syntax_tutorial.tex source file for syntax_tutorial.pdf
Updates to the syntax tutorial.
Fix deleting PRT nodes on the form.
Reminder to work on the hints.
Merge branch 'master' of github.com:maths/moodle-qtype_stack
LaTeX rendering using "external"-block.