Add Karel type and refactor.
Update tests to work with new class hierarchy.
Fix up naming of sub classes (STI) and tests.
Ajax maze builder form so we can have unified response.
Update tests to fit with STI type names.
s/turtle/artist
Fix method declaration.
Use remotipart for ajax file upload.
Add user to level create.
Make sure user is included in custom level.
Fix toolbox method name.
Add test for maze toolbox.
Merge pull request #521 from code-dot-org/karel-sti

Karel sti