Text direction tests updated

The HTML and CSS text direction tests in the Internationalization Activity test suite have been updated as follows:

• HTML5 and XHTML5 were added as new test formats
• tests now use strict DOCTYPEs
• reference graphics in the vertical text tests were improved
• the order of tests related to browser chrome was changed

In addition, a new results page was created for the tests about vertical text.

Other changes behind the scenes include gathering of all tests into a single PHP file (generatehtml.php is no longer used). Code in the PHP file was also streamlined.