Loading tutorials via URL
Serving list of tutorials from server
Using preference values to fill common elements (preference >= 100)
Small changes
Added json schema for all tutorial formats
Added version information to backend and frontend
Merge pull request #401 from dswd/use_preference

Using preference values to fill common elements (preference >= 100)
Merge pull request #405 from dswd/versions

Added version information to backend and frontend
Merge pull request #398 from dswd/tutorial_url

Tutorial url