Character encoding tests updated

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

• new tests were added to examine behaviour related to the byte-order mark and better represent the current detection algorithm for HTML5
• HTML5 was added as a new test format
• tests now use strict DOCTYPEs
• results pages were updated to reflect latest browser version behaviour, and to make it easier to see the assertions used for the tests

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.

The general improvements to the test and results pages mentioned above will be added to other tests over time.