Add header & some links to course landing page.
Remove artwork survey from teacher links.
add support for codeclimate test coverage reporting
Merge pull request #517 from code-dot-org/codeclimate-test-coverage

add support for codeclimate test coverage reporting
Automatically built.
add type column.
Start refactoring
Fix storng params.
Use iterated params for artist levels.
Add tests to make sure STI is working.
more tests to make sure STI is working.
Refactoring.
Add html and logic for karel builder.
Add test for maze/karel distinction in maze builder.