Import Document-contentType tests from presto-testo.
Rewrite the tests to use testharness.js.
Remove the old test runner.
Rewrite contenttype_setter.php in python.
Replace the images by small green squares.
Fix issues found by zcorpan.
Merge pull request #613 from w3c/presto/contentType

Import Document-contentType tests from presto-testo.